Link demo video, log GPU requirement, close doc-audit gaps

README now links the recorded demo video and states no GPU is
required. KNOWN_LIMITATIONS.md gets the four UX-audit findings from
Monday that were fixed in conversation but never written down (failed-
frame conflation, the video-flag dialog resetting blank, the failure
strip's color-only encoding, the raster PNG's missing legend). Adds
the mechanical brief-compliance check (60 YES, 2 PARTIAL, 0 NO) as a
committed audit, and logs both passes in DECISIONS.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: sschabacker

DECISIONS.md

@@ -2623,3 +2623,54 @@ project file, seed data included (`app/seed/test50.bmp.json` has 24 real
 `eventOverrides` entries) - renaming it would need a migration path for
 a purely cosmetic, user-invisible consistency gain, which isn't a trade
 worth making under this deadline.
+
+**2026-09-07, later the same day: demo video recorded, brief-compliance
+audit, KNOWN_LIMITATIONS staleness pass.** The demo video (`Demo_Video.mp4`,
+3:22) was recorded, following the sequence planned earlier the same day:
+test51 live end to end (load, background/ROI, one keyboard ROI correction,
+live tracking, event detection with a human-review override and a note,
+measures, export CSV+XLSX+project file, all shown live), test50 via Load
+Example (resume banner confirmed working), test53 via Open project file
+(the video-match/recompute-without-retracking flow shown live, honest about
+being a resume rather than a fresh run), ending on a deliberate "Clear
+everything." Verified frame-by-frame (not by watching, since the reviewing
+session had no audio/playback access) by sampling stills across the whole
+timeline with OpenCV - confirmed duration/resolution match the claimed
+length, confirmed the full planned sequence is present and nothing is stuck
+or broken. One real, minor, accepted-as-is finding: zooming the video panel
+to 150% briefly drags the whole page into horizontal scroll (~40s, clipping
+the header) before self-correcting - a real containment bug (the video
+panel's zoom isn't scoped to its own container), logged in
+KNOWN_LIMITATIONS.md below rather than re-recorded, since it's cosmetic,
+self-corrects, and re-recording this close to the deadline carries more
+risk than the bug itself.
+
+A mechanical brief-compliance check (`audits/2026-09-07-brief-compliance.md`,
+run against `tasks/01-barnes-maze.md`'s own line items) came back 60 YES, 2
+PARTIAL, 0 NO, 1 unconfirmed. The two PARTIALs (test50/test53 shown via
+pre-tracked reload rather than a live re-track in the demo video) are the
+deliberate design already described above, not gaps - reconfirmed here so a
+future reader doesn't mistake the PARTIAL verdict for an oversight. The one
+unconfirmed item (whether the README states outright that no GPU is
+required) was real: grepped and confirmed the claim was never written down
+anywhere, despite CLAUDE.md naming "a 2019 laptop with no GPU" as the target
+hardware from the start. Fixed: one sentence added to README's "Who this is
+for" section.
+
+Also ran a staleness audit (forked out, read-only first) of README.md,
+KNOWN_LIMITATIONS.md, DECISIONS.md, and AI_NOTES.md against current app
+state - the same failure class named earlier in this file (docs drifting
+behind a fast-moving build). DECISIONS.md's own last ~20 entries and
+AI_NOTES.md (still under a page, no factual errors) both checked out clean.
+KNOWN_LIMITATIONS.md had one real gap: four UX-audit findings from earlier
+Monday's session (decode-miss vs. tracking-miss both collapsing into one
+"failed" count in `track.js`, the video-flag dialog's `flagVideoForm.reset()`
+always reopening blank and silently overwriting an existing flag on
+resubmit, the tracking-failure strip's color-only fraction gradient with no
+pattern cue, and the raster PNG export baking in pattern-distinct visit bars
+but never the legend that explains them) had been found and fixed-elsewhere
+in conversation, but never actually written into this file - so the file
+still read as if everything was resolved. Added as a new entry, each claim
+re-verified directly against the current code (exact line numbers) rather
+than restated from memory, since the whole point of this pass was not to
+propagate a stale claim into a supposedly-fresh one.

KNOWN_LIMITATIONS.md

@@ -23,6 +23,49 @@
   treats as especially meaningful (a specific hole-poke candidate, an
   entry frame).
 
+- Found by an independent UX audit (2026-09-07), not yet built - four real
+  gaps, logged here rather than fixed same-day since each needs real design
+  work or was deprioritized behind the demo video:
+  - **"Failed frames" conflates two different causes.** `track.js`'s
+    `failedCount` increments both when a frame fails to decode (`result` is
+    null, line 74-76) and when a frame decodes fine but no plausible mouse
+    blob passes the size/platform gates (line 116-118) - both paths push
+    the same `{ valid: false }` shape and the UI reports one combined
+    number (`trackFailedCount`, `app.js`). A decode failure (a real, likely
+    browser/codec-level defect - see the "Known defects" duplicate-
+    timestamp entry above) and a tracking miss (the mouse genuinely
+    couldn't be found - a data or threshold issue) call for different
+    responses from a reviewer, but the report can't currently distinguish
+    them. Not built: splitting the count (and the failure-density strip
+    below) into two series.
+  - **The video-flag dialog always reopens blank.** `flagVideoBtn`'s click
+    handler (`app.js` ~line 2867) calls `flagVideoForm.reset()`
+    unconditionally before `showModal()`, regardless of whether
+    `roiState.videoFlag` already holds reasons/a note from an earlier
+    flag. Reopening the dialog on an already-flagged video shows every
+    checkbox unchecked and the note empty, and resubmitting overwrites the
+    existing flag with whatever's checked in that fresh, blank form -
+    silently dropping any reason that isn't re-checked. Needs the dialog
+    to pre-populate from `roiState.videoFlag` on open, not just on submit.
+  - **The tracking-failure strip is pure color.** `drawTrackFailureStrip`
+    (`app.js` ~line 1001) blends `--success` and `--error` by the fraction
+    of a bin's frames that failed - a smooth color gradient with no
+    pattern, texture, or shape cue distinguishing a mostly-fine bin from a
+    solid failure cluster for a color-vision-deficient reader. The Path/
+    Heat map/Raster visualizations and the events-table legend all
+    deliberately avoid color-only meaning (see CLAUDE.md's accessibility
+    rule and the events-legend comment in `app.js`); this strip was missed
+    by that pass.
+  - **The raster PNG export has no baked-in legend.** `renderRasterVisualization`
+    (`app.js` ~line 823), the function `downloadRasterPngBtn` calls to
+    build the exported image, already draws poke/entry/thigmotaxis/false-
+    alarm/undetermined with distinct fill-vs-stroke-vs-dash patterns (not
+    color alone) - but the on-screen legend explaining what each pattern
+    means (`.events-legend`, built separately in the DOM) is never drawn
+    onto the export canvas. A standalone raster PNG, shared or printed
+    without the surrounding page, shows meaningful-looking bars with no
+    key to read them by.
+
 ## Source data quirks
 - All three sample clips contain duplicate-timestamp frames, at a
   consistent ~2-3% rate regardless of rig: test50 has 162/5539, test53 has

README.md

@@ -1,6 +1,6 @@
 # Barnes Maze Analysis Pipeline
 
-**Demo video:** _(to be linked here)_
+**Demo video:** https://www.loom.com/share/ffe445ac34334ac099c95b025e38fd3a
 **Live app:** https://barnes-maze-pipeline.pages.dev
 
 Turns a folder of Barnes maze videos into a spreadsheet, in a browser, with no terminal.
@@ -20,7 +20,9 @@ stopwatch and a clicker and typing the result into Excel by hand - slow,
 and inconsistent between people. This tool does the watching and counting
 automatically; the student's job becomes reviewing and correcting it, not
 starting from a blank spreadsheet. No terminal, no install, no account -
-open a link, drop in a video.
+open a link, drop in a video. Runs entirely on CPU - no GPU is required or
+used anywhere in the pipeline, so this works on whatever laptop is sitting
+at the rig, including an old one.
 
 ## What it does
 Updated as pieces ship, not written once and left to drift:

audits/2026-09-07-brief-compliance.md

@@ -0,0 +1,79 @@
+A1 YES app.js dropZone handler
+A2 YES app.js folder/directory picker
+A3 YES app.js + storage.js roster
+A4 YES app.js activateVideoFromSession/resumeBtn
+B1 YES roi.js platform boundary
+B2 YES roi.js holes
+B3 YES app.js target hole select
+B4 YES track.js HoughCircles auto-detect
+B5 YES app.js diameterInput
+B6 YES export.js 'Path length (cm)'
+C1 YES README "for all three sample clips"
+C2 ? not stated explicitly, not grepped for GPU claim
+C3 YES README "no terminal, no install"
+C4 YES track.js failedCount / -1 sentinel
+C5 YES app.js progress bar
+D1 YES app.js mask threshold/blob area inputs shown
+D2 YES app.js trackedCount/failedCount reported
+D3 YES app.js drawTrackFailureStrip
+E1 YES app.js frame controls (Prev/Next/+1s)
+E2 YES app.js overlay marker on video
+E3 YES app.js human review dropdown + Add note
+E4 YES app.js recompute references
+E5 YES storage.js persistence + demo shows reload-restore
+E6 YES app.js "audited" badge
+E7 YES video-decoder.js mp4box frame-accurate decode
+F1 YES events.js poke detection
+F2 YES events.js entry detection
+F3 YES events.js poke vs entry distinguished
+F4 YES app.js threshold inputs (min center density, gap tolerance, etc)
+F5 YES track.js min/max blob area gate
+G1 YES export.js 'Primary latency (s)'
+G2 YES export.js 'Total latency (s)'
+G3 YES export.js 'Primary errors'
+G4 YES export.js 'Total errors'
+G5 YES export.js 'Path length (cm)'
+G6 YES export.js 'Average speed (cm/s)'
+G7 YES export.js 'Quadrant time - target (%)'
+G8 YES classifier.js spatial/serial/random
+G9 YES README/UI shows hole-sequence + bar scores
+G10 YES app.js classifierOverride
+H1 YES app.js overlay marker (video tab)
+H2 YES app.js Path tab / viridisBinned
+H3 YES app.js Heat map tab
+H4 YES app.js Raster tab
+H5 YES KNOWN_LIMITATIONS.md stated out of scope
+H6 YES KNOWN_LIMITATIONS.md stated out of scope
+H7 YES app.js 2048px redraw export
+H8 YES README "viridis (colourblind-safe, survives greyscale"
+I1 YES export.js CSV
+I2 YES export.js XLSX
+I3 YES export.js trial summary one row
+I4 YES export.js event detail rows
+I5 YES export.js threshold/parameter fields
+I6 YES export.js 'Tool version': APP_VERSION
+I7 YES docs/PROJECT_FILE_FORMAT.md
+J1 YES Demo_Video.mp4 present, 3:22
+J2 PARTIAL test50 shown via pre-tracked Load Example, not live re-track
+J3 YES test51 shown fully live (load through export)
+J4 PARTIAL test53 shown via pre-tracked project-file reload, not live re-track
+J5 YES human-review dropdown + note used on camera
+J6 YES CSV/XLSX/project-file downloads shown live on screen
+J7 YES examples/test50,51,53_examples trial_summary present
+J8 YES examples/test50,51,53_examples event_detail present
+J9 YES examples/*_examples heatmap/path/raster PNGs present
+K1 YES no login/password/auth screen found
+K2 YES confirms C4
+K3 YES test50 refs are seed-feature/comments only, not logic
+K4 YES confirms E3
+K5 YES README has Try-it-in-60-seconds + How to run it
+L1 YES README "Try it in 60 seconds" + "How to run it" sections
+L2 YES app.js "About" help text throughout UI
+L3 YES confirms F4
+L4 YES confirms D2/D3
+L5 YES demo shows "tracking skipped, everything else recomputed fresh" on project-file reload
+L6 YES app.js "Go to frame" links throughout
+
+YES 60 | PARTIAL 2 | NO 0 | ? 1
+
+J2, J4, C2