docs(release): 2.6.3 release notes and test plan, folding in the internal 2.6.2

[brickbots]

Summary

Prepares the 2.6.3 release documents covering the full v2.6.1..main delta, with the internal-only 2.6.2's changes folded in.

release_notes/2.6.3.md — retitled from the 2.6.2 draft, with the version story stated up front (no public 2.6.2; the pause; why 2.6.3 supersedes it), and extended past #631's coverage point with the five PRs that landed since:

• Stellarium push (Stellarium push #621) — new feature section, including the LX200 dialect fixes and the SkySafari-protecting gates
• Chart center-object readout (feat(chart): name the center object on an optional readout #633, ADR 0031)
• GPS MSG row on STATUS (feat(gps): show the last GPS event and its age on the STATUS screen #635, ADR 0032)
• Web form validation at the API (Validate equipment and GPS form input at the API, not just the browser #571, ADR 0033)
• Unknown optical train (fix(optics): no FOV gate for frames from an unknown optical train #632) — the --camera debug fix and the self-heal guard
• Developer section updated: ADRs 0031–0033, GPS bounded context, test count 1,305 → 1,531, i18n 23 new msgids / 694 per catalog
• Two new known sharp edges: catalog-designation naming in the readout, and Stellarium being protocol-verified but not yet field-verified

release_notes/release-2.6.3-test-plan.md — supersedes the 2.6.2 plan (kept as reference). Highlights:

• Release mechanics section: the cut is not a fast-forward anymore. release carries the pause commit (b485e3be, version.txt → 2.6.1); the merge conflicts on version.txt only, and the resolved tree is byte-identical to main (verified with git merge-tree), so testing main is still testing the cut.
• The un-pause criterion is explicit: Gate 3's rev4 12 mm self-heal validation is the specific evidence that justifies lifting b485e3be's pause.
• Upgrade gates cover both populations: 2.6.1 field devices and 2.6.2 internal devices.
• New bench gates for Nearby/observed-cache, the chart readout, the GPS MSG row, and web forms (happy path first — the new risk is over-strict validation); live-app gates for SkySafari regression and Stellarium (no hardware evidence banked yet).
• Gate 1 verified green on main @ 0f54d7fc (2026-08-25): ruff lint+format clean, mypy clean, 1,531 smoke+unit passing, -nW docs build clean, all four .mo files byte-identical to a fresh compile.

Verification

• pytest -m "smoke or unit": 1,531 passed
• ruff check / ruff format --check: clean
• mypy PiFinder: clean (fresh cache, submodule initialised)
• sphinx -nW: build succeeded, 0 warnings
• All commit/branch facts in the documents verified against git merge-tree, rev-list, and branch tips

🤖 Generated with Claude Code

https://claude.ai/code/session_01Wun9k6C2jewB1yRXhU49Dy