Denoise UI

[henryhng]

Stacked diff on top of #207: henryhng/quantem.widget@denoise-v2...henryhng:quantem.widget:denoise-ui

Summary

Frontend controls and frame caching for ShowDiffraction denoise.

Verification

• Checks run: npm run build, npm run typecheck, npm test (129 passed), PYTHONPATH=src pytest -q tests/test_showdiffraction_denoise.py tests/test_showdiffraction_frontend_source.py (14 passed)
• User workflow: widget HTML in Chromium; Denoise/Detect dropdowns and Detect View toggle render
• Data: synthetic Poisson ring pattern, 256x256, float32
• Backend and hardware: CPU
• Load/render/interaction timing: filtered frames cached per (frame, mode); nlm about 0.1 s per 512x512 frame, gaussian/anscombe instant
• Evidence artifacts or screenshots: n/a.

Checklist

• 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. n/a — no notebook changes.
• Only the sections below that this PR touches are kept; the rest are deleted from this description.

UI design and theming — frontend / viewer changes

• The frontend follows the local viewer patterns instead of inventing a new design system; the dropdowns reuse the existing Color/Scale select row and the toggle joins the existing side-menu array.
• Controls are compact and content-sized: menus for the option sets, a side-menu toggle for the binary.
• Compact labels stay grouped with the control they name on mobile and narrow layouts.
• Compact widget control labels do not use decorative colons.
• Command buttons use Title Case.
• The widget supports both light and dark notebook/docs themes; the new controls use the shared themedSelect and side-menu styles.
• The widget has no hardcoded dark-only or light-only assumptions.
• Histogram UI matches the existing Show2D-style interaction. n/a
• Hover inspection is independent of selection. n/a
• New or changed widget interactions have a matching storyboard story. n/a.

---

This PR workflow follows the packaging standards for reproducible scientific software described in scikit-package: S. Lee, C. Myers, A. Yang, T. Zhang, Y. Xiao, and S. J. L. Billinge, Digital Discovery (2026), DOI 10.1039/d6dd00121a.