fix(progress-report): one nav group, one id=stamp, no build-plan.html note (#479 items 1–3)

[MendixMau]

Direct lane

What changed and why (one paragraph):
Fixes #479 (items 1–3). Item 4 (page names) is left open for the maintainer. Top bar: the sticky .snav bar loses the Stage P 0 … 6 chips (they repeated the stage rail right below) and the IntersectionObserver that outlined them; it is now one group of section links, Stages · Build · Pages · Tips (Tips only when a session log was read), with Stages jumping to the stage rail heading (id=stages). #stages and #build-detail get the same 56px scroll margin as the other targets, so they do not land under the bar. The bar stays sticky with the existing phone rule (nowrap; overflow-x:auto under 520px), every #stage-N card anchor stays, and the header line now starts with Current stage: Stage N: <name>, linked to its card (plain Current stage: unknown when PROJECT.md names no stage). id=stamp: five elements carried it (Last updated, session log last event, the build/score/plan notes, the footer note). Only "Last updated" keeps it. The others get unique ids (lastevent, lastbuild, modelscore, planread, rebuildnote) plus a data-stamp marker. The one reader that depended on the id, build-plan-status.sh --refresh's no-rewrite comparison, now filters id=stamp|data-stamp. Pages written before this change still compare. The filter now depends on both scripts: a project whose bin/build-plan-status.sh is locally edited keeps the old id=stamp filter after sync (sync reports a modified copy and does not overwrite it). Such a project's page is then rewritten on every refresh until it runs sync-project.sh --only-bin build-plan-status.sh --upgrade-bin build-plan-status.sh. The autoreload script never read stamp; it reads livetxt/livebtn, which sit on the id=stamp line and stay unique. Header: "replaces the former build-plan.html" is removed (the note stays under "How this was measured" and in the release notes).

Impact

Row	Answer
Process — human steps or gates added/removed; does anything new block; new stage artifacts	none: generated page layout only; nothing new blocks
Dependencies — shared files touched; order vs other open PRs; new tools/platform assumptions; new artifact reads + their producer	project-bin/progress-report.py, project-bin/build-plan-status.sh (refresh filter only). The two must ship together: a project with a locally edited bin/build-plan-status.sh keeps the old filter after sync and rewrites the page on every refresh, so it needs sync-project.sh --only-bin build-plan-status.sh --upgrade-bin build-plan-status.sh alongside this. Builds on #472 and #475, both on master. No new tools, no new artifact reads
Context cost — always-loaded words per role	none: no routed or always-loaded file touched
Behaviour — A/B result for agent-read text	n/a: scripts only
Runtime — seconds/resources added or saved	n/a (one less IntersectionObserver in the page)

Field evidence: invented demo projects in the fixtures only. The rendered P7 page has grep -c 'id=stamp' = 1 and no duplicate ids. --refresh leaves an unchanged page byte-identical. Not yet re-run on a live project.

• No client data anywhere in the diff (leak guard clean; whole-word client-name grep of added lines = 0)
• Size cap: 5 files, about +75/−17 including fixtures and CHANGELOG
• Test tier reached: T1, the scoped fixtures. test-progress-report 101/0, -polish 53/0 (new P7: nav, scroll margins, unknown stage, stamps), -pages 54/0, -field-fixes 105/0 (F11 flipped, F14 stamp assertions), -gitignore 15/0, test-build-plan-json 70/0, test-build-plan-status-args 6/0, test-windows-msys-paths 9/0. check-scripts, check-portability, check-pr-discipline origin/master and the leak guard are clean
• For a changed instrument: no parser of tool output changed; path handling is untouched, so the layout and platform cases do not apply
• For a new skill: n/a
• CHANGELOG.md line appended, credited "— MendixMau (review 2026-10-20)"
• New bug entries: n/a

https://claude.ai/code/session_01VJgWP5vEoAsNsJYqCDMGNw

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