diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index 8524ffef..8915220d 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -1,20 +1,9 @@
 <!--
-This is the canonical operational checklist for quantem.widget pull requests.
-It is intentionally thorough so humans and coding agents can select the right
-gates and leave reproducible, automation-friendly evidence. Links are absolute
-because relative links do not resolve in PR descriptions.
-
-How to use: keep the Core checklist, then expand and complete only the
-sections your change touches. Delete sections that do not apply — a reviewer
-should only see boxes that are relevant to this PR. Either verify each box
-yourself or have a coding agent verify it and check it off for you; mark an
-item that is in a relevant section but does not apply as "n/a — reason".
-
-This PR workflow follows the scientific-software packaging standards described
-in: S. Lee, C. Myers, A. Yang, T. Zhang, Y. Xiao, and S. J. L. Billinge,
-"Scikit-package - software packaging standards and roadmap for sharing
-reproducible scientific software", Digital Discovery (2026).
-https://doi.org/10.1039/d6dd00121a
+This is the canonical operational checklist for quantem.widget pull requests. It is intentionally thorough so humans and coding agents can select the right gates and leave reproducible, automation-friendly evidence. Links are absolute because relative links do not resolve in PR descriptions.
+
+How to use: keep the Core checklist, then expand and complete only the sections your change touches. Delete sections that do not apply — a reviewer should only see boxes that are relevant to this PR. Either verify each box yourself or have a coding agent verify it and check it off for you; mark an item that is in a relevant section but does not apply as "n/a — reason".
+
+This PR workflow follows the scientific-software packaging standards described in: S. Lee, C. Myers, A. Yang, T. Zhang, Y. Xiao, and S. J. L. Billinge, "Scikit-package - software packaging standards and roadmap for sharing reproducible scientific software", Digital Discovery (2026). https://doi.org/10.1039/d6dd00121a
 -->
 
 ## Summary
@@ -24,9 +13,7 @@ https://doi.org/10.1039/d6dd00121a
 ## Verification
 
 <!--
-Keep this concise and use "n/a" where a field does not apply. These structured
-fields help reviewers and coding agents reproduce the scientific workflow and
-select any missing gates without relying on private logs.
+Keep this concise and use "n/a" where a field does not apply. These structured fields help reviewers and coding agents reproduce the scientific workflow and select any missing gates without relying on private logs.
 
 - Checks run:
 - User workflow exercised:
@@ -38,176 +25,73 @@ select any missing gates without relying on private logs.
 
 ## Core checklist (every PR)
 
-- [ ] The change includes focused tests for Python state/export behavior and
-  frontend build coverage where possible; start with `PYTHONPATH=src:. pytest -q`
-  and `npm run build`, or run `scripts/widget_local_signoff.sh`.
-- [ ] Before committing, inspect `git status --short` and `git diff --stat`;
-  do not commit generated HTML, docs builds, screenshots, local notebooks,
-  private data, or machine-specific notes.
-- [ ] Committed notebooks carry NO baked widget state (`metadata.widgets`) and
-  pass `scripts/check_notebook_sizes.py`. The docs CI executes tutorials at
-  build time (`execute_notebooks: force` in `docs/_config.yml`) and bakes
-  widget state into the published HTML only — never commit a re-executed
-  notebook with stored widget state, and never switch the docs build to
-  `cache` mode (it silently drops widget state and blanks every widget).
-  Saving a notebook after running widget cells stores that state silently;
-  strip it before committing:
-  `jq 'del(.metadata.widgets)' <nb>.ipynb > tmp && mv tmp <nb>.ipynb`
-- [ ] Only the sections below that this PR touches are kept; the rest are
-  deleted from this description.
+- [ ] The change includes focused tests for Python state/export behavior and frontend build coverage where possible; start with `PYTHONPATH=src:. pytest -q` and `npm run build`, or run `scripts/widget_local_signoff.sh`.
+- [ ] Before committing, inspect `git status --short` and `git diff --stat`; do not commit generated HTML, docs builds, screenshots, local notebooks, private data, or machine-specific notes.
+- [ ] Committed notebooks carry NO baked widget state (`metadata.widgets`) and pass `scripts/check_notebook_sizes.py`. The docs CI executes tutorials at build time (`execute_notebooks: force` in `docs/_config.yml`) and bakes widget state into the published HTML only — never commit a re-executed notebook with stored widget state, and never switch the docs build to `cache` mode (it silently drops widget state and blanks every widget). Saving a notebook after running widget cells stores that state silently; strip it before committing: `jq 'del(.metadata.widgets)' <nb>.ipynb > tmp && mv tmp <nb>.ipynb`
+- [ ] Only the sections below that this PR touches are kept; the rest are deleted from this description.
 
 <details>
 <summary><b>Python API and docs</b> — new widget, loader, or API change</summary>
 
-- [ ] The widget has a small, stable Python API with NumPy-style docs, helpful
-  errors, and `(row, col)` coordinate wording where positions are shown.
-- [ ] Every new public widget or API is exported from `quantem.widget`, listed
-  in the README widget catalog and import example, linked from the API index
-  and documentation sidebar, and recorded under **Unreleased** in
-  `CHANGELOG.md`.
-- [ ] Documentation includes a minimal tutorial notebook under
-  [docs/tutorials](https://github.com/electronmicroscopy/quantem.widget/tree/main/docs/tutorials)
-  and an API page under
-  [docs/api](https://github.com/electronmicroscopy/quantem.widget/tree/main/docs/api)
-  when a public widget or loader is added.
-- [ ] Tutorial notebooks avoid unnecessary `display(...)` and extra display
-  imports; let the returned widget render naturally.
-- [ ] Synthetic-data generation cells in tutorial notebooks are collapsed with
-  the `hide-input` cell tag and a descriptive toggle label via cell metadata
-  `mystnb.code_prompt_show` (for example "Show synthetic data generation
-  code"), never the default "Show code cell source". Keep widget-construction
-  code and real-data loader calls visible; split a cell that mixes the two.
+- [ ] The widget has a small, stable Python API with NumPy-style docs, helpful errors, and `(row, col)` coordinate wording where positions are shown.
+- [ ] Every new public widget or API is exported from `quantem.widget`, listed in the README widget catalog and import example, linked from the API index and documentation sidebar, and recorded under **Unreleased** in `CHANGELOG.md`.
+- [ ] Documentation includes a minimal tutorial notebook under [docs/tutorials](https://github.com/electronmicroscopy/quantem.widget/tree/main/docs/tutorials) and an API page under [docs/api](https://github.com/electronmicroscopy/quantem.widget/tree/main/docs/api) when a public widget or loader is added.
+- [ ] Tutorial notebooks avoid unnecessary `display(...)` and extra display imports; let the returned widget render naturally.
+- [ ] Synthetic-data generation cells in tutorial notebooks are collapsed with the `hide-input` cell tag and a descriptive toggle label via cell metadata `mystnb.code_prompt_show` (for example "Show synthetic data generation code"), never the default "Show code cell source". Keep widget-construction code and real-data loader calls visible; split a cell that mixes the two.
 
 </details>
 
 <details>
 <summary><b>UI design and theming</b> — frontend / viewer changes</summary>
 
-- [ ] The frontend follows the local viewer patterns instead of inventing a new
-  design system; compare against
-  [Show2D](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/show2d.ipynb),
-  [Show3D](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/show3d.ipynb),
-  [Show3DSlices](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/show3dslices.ipynb),
-  [Show4DSTEM](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/show4dstem.ipynb), and
-  [ShowEDS](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/showeds.ipynb). Follow the
-  [widget UI protocol](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/widget-ui-protocol.md).
-- [ ] Controls are compact and content-sized: use icon/text buttons for
-  commands, switches for binary options, sliders for numeric values, menus for
-  option sets, and avoid stretched empty control bars.
-- [ ] Compact labels stay grouped with the control they name on mobile and
-  narrow layouts. A row may wrap, but `Auto`, `Smooth`, `Zoom`, `Pan`,
-  `Contrast`, `fps`, `avg`, and similar labels must not separate from their
-  switch, menu, slider, or button.
-- [ ] Compact widget control labels do not use decorative colons. Prefer
-  `Scale`, `Color`, `Auto`, `Link`, `Zoom`, `Pan`, and `ROI` in dense toolbar
-  rows; keep colons for explanatory prose and tooltips.
-- [ ] Command buttons use Title Case, for example `Copy`, `Export`, `Reset`,
-  `Add`, `Clear`, and `Undo`. Keep scientific acronyms and file formats
-  uppercase, for example `FFT`, `ROI`, `BF`, `ADF`, `HTML`, `PNG`, and `MP4`.
-- [ ] The widget supports both light and dark notebook/docs themes: all labels,
-  borders, controls, plots, histograms, ROI handles, status text, and export UI
-  remain readable.
-- [ ] The widget has no hardcoded dark-only or light-only assumptions in plots,
-  canvas backgrounds, tooltips, menus, or exported HTML.
-- [ ] Histogram UI matches the existing Show2D-style interaction: compact panel,
-  no extra whitespace, draggable min/max handles, fast center drag, and no
-  visible lag.
-- [ ] Hover inspection is independent of selection. In Show2D, Show3D,
-  Show4DSTEM, and other multi-target widgets, hover at least two unselected
-  panels/regions and verify coordinates, value/readout, labels, detector/ROI
-  context, and stats follow the hovered target while edit controls remain
-  scoped to the explicitly selected target.
-- [ ] New or changed widget interactions have a matching storyboard story in
-  [docs/maintainer/storyboard-&lt;widget&gt;.md](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/storyboard.md)
-  (add stories for new behavior, update stale ones), and the storyboard
-  drive-test was run for the affected widget with the driven story IDs
-  reported.
+- [ ] The frontend follows the local viewer patterns instead of inventing a new design system; compare against [Show2D](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/show2d.ipynb), [Show3D](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/show3d.ipynb), [Show3DSlices](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/show3dslices.ipynb), [Show4DSTEM](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/show4dstem.ipynb), and [ShowEDS](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/showeds.ipynb). Follow the [widget UI protocol](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/widget-ui-protocol.md).
+- [ ] Controls are compact and content-sized: use icon/text buttons for commands, switches for binary options, sliders for numeric values, menus for option sets, and avoid stretched empty control bars.
+- [ ] Compact labels stay grouped with the control they name on mobile and narrow layouts. A row may wrap, but `Auto`, `Smooth`, `Zoom`, `Pan`, `Contrast`, `fps`, `avg`, and similar labels must not separate from their switch, menu, slider, or button.
+- [ ] Compact widget control labels do not use decorative colons. Prefer `Scale`, `Color`, `Auto`, `Link`, `Zoom`, `Pan`, and `ROI` in dense toolbar rows; keep colons for explanatory prose and tooltips.
+- [ ] Command buttons use Title Case, for example `Copy`, `Export`, `Reset`, `Add`, `Clear`, and `Undo`. Keep scientific acronyms and file formats uppercase, for example `FFT`, `ROI`, `BF`, `ADF`, `HTML`, `PNG`, and `MP4`.
+- [ ] The widget supports both light and dark notebook/docs themes: all labels, borders, controls, plots, histograms, ROI handles, status text, and export UI remain readable.
+- [ ] The widget has no hardcoded dark-only or light-only assumptions in plots, canvas backgrounds, tooltips, menus, or exported HTML.
+- [ ] Histogram UI matches the existing Show2D-style interaction: compact panel, no extra whitespace, draggable min/max handles, fast center drag, and no visible lag.
+- [ ] Hover inspection is independent of selection. In Show2D, Show3D, Show4DSTEM, and other multi-target widgets, hover at least two unselected panels/regions and verify coordinates, value/readout, labels, detector/ROI context, and stats follow the hovered target while edit controls remain scoped to the explicitly selected target.
+- [ ] New or changed widget interactions have a matching storyboard story in [docs/maintainer/storyboard-&lt;widget&gt;.md](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/storyboard.md) (add stories for new behavior, update stale ones), and the storyboard drive-test was run for the affected widget with the driven story IDs reported.
 
 </details>
 
 <details>
 <summary><b>Performance and real-time interaction</b> — drag, live controls, big data paths</summary>
 
-- [ ] Any draggable selector has live preview separate from committed widget
-  state; use refs/CSS transforms or an equivalent fast path during drag. See
-  [performance notes](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/widget-performance.md).
-- [ ] Use [Show4DSTEM](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/show4dstem.ipynb)
-  detector dragging and
-  [ShowEDS](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/showeds.ipynb)
-  energy-band dragging as the real-time UX benchmark: aim for 60 FPS when
-  feasible and keep live controls at 30 FPS or better.
-- [ ] Real-time interactions are browser-driven and verified by actually
-  dragging controls in JupyterLab or exported HTML, not only by reading code or
-  unit tests.
-- [ ] Show4DSTEM live-scope workflows append new ready `*_master.h5`
-  acquisitions into the same live viewer without rebuilding the notebook. Verify
-  new masters appear in the Dataset slider, partial files are skipped until
-  ready, and detector/scan interactions remain real time after append. See
-  [Show4DSTEM live scope folders](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/api/show4dstem.md#live-scope-folders).
-- [ ] Performance reports separate load time, widget build time, first browser
-  paint, and interaction FPS/latency. Include data shape, dtype, raw size,
-  backend, and any crop/bin/downsample/quantization. Prefer `verbose=True`
-  output that users and agents can copy; use `quantem.widget.profile_widget`
-  for profiling notebooks when possible. See
-  [performance notes](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/widget-performance.md).
-- [ ] For interaction-sensitive changes, run
-  `scripts/widget_local_signoff.sh --quick --browser` for exported HTML/UI
-  paths, fix issues immediately, rebuild, refresh, and redrive before claiming
-  the widget is ready. See
-  [Automation](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/automation.md) and
-  [Agent signoff](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/widget-agent-signoff.md).
-- [ ] Expensive work avoids Python/kernel round trips during pointer movement;
-  use WebGPU, typed arrays, cached indexes, workers, or throttled schedulers
-  where the widget interaction requires live feedback.
+- [ ] Any draggable selector has live preview separate from committed widget state; use refs/CSS transforms or an equivalent fast path during drag. See [performance notes](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/widget-performance.md).
+- [ ] Use [Show4DSTEM](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/show4dstem.ipynb) detector dragging and [ShowEDS](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/tutorials/showeds.ipynb) energy-band dragging as the real-time UX benchmark: aim for 60 FPS when feasible and keep live controls at 30 FPS or better.
+- [ ] Real-time interactions are browser-driven and verified by actually dragging controls in JupyterLab or exported HTML, not only by reading code or unit tests.
+- [ ] Show4DSTEM live-scope workflows append new ready `*_master.h5` acquisitions into the same live viewer without rebuilding the notebook. Verify new masters appear in the Dataset slider, partial files are skipped until ready, and detector/scan interactions remain real time after append. See [Show4DSTEM live scope folders](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/api/show4dstem.md#live-scope-folders).
+- [ ] Performance reports separate load time, widget build time, first browser paint, and interaction FPS/latency. Include data shape, dtype, raw size, backend, and any crop/bin/downsample/quantization. Prefer `verbose=True` output that users and agents can copy; use `quantem.widget.profile_widget` for profiling notebooks when possible. See [performance notes](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/widget-performance.md).
+- [ ] For interaction-sensitive changes, run `scripts/widget_local_signoff.sh --quick --browser` for exported HTML/UI paths, fix issues immediately, rebuild, refresh, and redrive before claiming the widget is ready. See [Automation](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/automation.md) and [Agent signoff](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/maintainer/widget-agent-signoff.md).
+- [ ] Expensive work avoids Python/kernel round trips during pointer movement; use WebGPU, typed arrays, cached indexes, workers, or throttled schedulers where the widget interaction requires live feedback.
 
 </details>
 
 <details>
 <summary><b>Data honesty and repo size</b> — data loaders, tutorial data, CI fixtures</summary>
 
-- [ ] Large scientific data stays honest about precision and size: do not
-  silently crop, bin, downsample, quantize, or materialize sparse zeros.
-- [ ] Any binning/downsampling is explicit in the API and documentation, with
-  the reducer named clearly, for example mean, sum, or display-scaled `uint8`.
-- [ ] Keep `main` lightweight: small real rendered examples are fine, but large
-  tutorial arrays or HTML payloads should be generated during docs builds or
-  downloaded from public data hosting only when the size justifies it.
-- [ ] Keep clone and install size small for microscope PCs. Real tutorial data
-  belongs in public data hosting such as Hugging Face datasets, Zenodo, or
-  release assets, then gets downloaded and cached by tutorial helpers at run
-  time. Do not commit large real arrays, generated HTML, or rendered docs
-  branches to this repository just to make examples work.
-- [ ] CI should test data-loading protocol with tiny deterministic fixtures or
-  monkeypatched downloads. Full real-data downloads are reserved for docs builds,
-  release signoff, or local performance checks that explicitly opt in.
+- [ ] Large scientific data stays honest about precision and size: do not silently crop, bin, downsample, quantize, or materialize sparse zeros.
+- [ ] Any binning/downsampling is explicit in the API and documentation, with the reducer named clearly, for example mean, sum, or display-scaled `uint8`.
+- [ ] Keep `main` lightweight: small real rendered examples are fine, but large tutorial arrays or HTML payloads should be generated during docs builds or downloaded from public data hosting only when the size justifies it.
+- [ ] Keep clone and install size small for microscope PCs. Real tutorial data belongs in public data hosting such as Hugging Face datasets, Zenodo, or release assets, then gets downloaded and cached by tutorial helpers at run time. Do not commit large real arrays, generated HTML, or rendered docs branches to this repository just to make examples work.
+- [ ] CI should test data-loading protocol with tiny deterministic fixtures or monkeypatched downloads. Full real-data downloads are reserved for docs builds, release signoff, or local performance checks that explicitly opt in.
 
 </details>
 
 <details>
 <summary><b>Export and saved state</b> — HTML export, widget state, sharing</summary>
 
-- [ ] The widget exposes `export_html(path=None, title=None, mode="single",
-  encoding="full", downsample=None)` when it can be exported. Follow the
-  [HTML export protocol](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/api/html-export.md).
-- [ ] If the widget has an in-widget **Export** button, it uses the standard
-  export traits and reports filename, mode, encoding/downsample choice, and
-  output size.
-- [ ] Saved Jupyter widget state works: after interacting, Cmd+S, close/reopen
-  in JupyterLab, and confirm the view restores without rerunning cells when the
-  environment supports saved widget state.
-- [ ] Standalone HTML works without a live Python kernel, and the exported page
-  preserves the intended theme, viewport, interaction state, and scale/contrast
-  state.
-- [ ] GitHub sharing is treated separately from live HTML: GitHub notebook
-  previews should use static compressed widget pictures, never heavy live widget
-  state. See [GitHub preview](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/github-preview.md).
+- [ ] The widget exposes `export_html(path=None, title=None, mode="single", encoding="full", downsample=None)` when it can be exported. Follow the [HTML export protocol](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/api/html-export.md).
+- [ ] If the widget has an in-widget **Export** button, it uses the standard export traits and reports filename, mode, encoding/downsample choice, and output size.
+- [ ] Saved Jupyter widget state works: after interacting, Cmd+S, close/reopen in JupyterLab, and confirm the view restores without rerunning cells when the environment supports saved widget state.
+- [ ] Standalone HTML works without a live Python kernel, and the exported page preserves the intended theme, viewport, interaction state, and scale/contrast state.
+- [ ] GitHub sharing is treated separately from live HTML: GitHub notebook previews should use static compressed widget pictures, never heavy live widget state. See [GitHub preview](https://github.com/electronmicroscopy/quantem.widget/blob/main/docs/github-preview.md).
 
 </details>
 
 ---
 
-This PR workflow follows the packaging standards for reproducible scientific
-software described in [scikit-package](https://doi.org/10.1039/d6dd00121a):
-S. Lee, C. Myers, A. Yang, T. Zhang, Y. Xiao, and S. J. L. Billinge,
-*Digital Discovery* (2026), DOI
-[10.1039/d6dd00121a](https://doi.org/10.1039/d6dd00121a).
+This PR workflow follows the packaging standards for reproducible scientific software described in [scikit-package](https://doi.org/10.1039/d6dd00121a): S. Lee, C. Myers, A. Yang, T. Zhang, Y. Xiao, and S. J. L. Billinge, *Digital Discovery* (2026), DOI [10.1039/d6dd00121a](https://doi.org/10.1039/d6dd00121a).