Completes M18 on top of the WIP checkpoint (6a703c3). Three lanes (H/J/K) depend only on
what this freezes.
- synthetic.py: base testsrc2 saturation/brightness-muted so its magenta/cyan colour bars
don't swamp lane H's colour detector; the two moving markers stay the only detectable blobs.
- Frontend (step 6): friendTracks.js stub (never-throws, fx.js pattern) wired into main.js;
hidden #btn-friends + #friends-panel; state.tracks loaded when manifest.has_tracks.
- Tests (step 8): test_tracks_foundation.py (20) — DB helpers, /api/tracks routes, solve
degradation, manifest.has_tracks, frozen OOK protocol + encoders, track_truth shape, the
projection round-trip (rendered pixels back-project to 3D truth, worst err <1e-3 → lane H's
median<0.3 reachable by construction), and a real-ffmpeg render test proving marker A is the
dominant magenta blob after base-muting.
- CR-6: the two sanctioned M18 test-lock edits (test_api manifest key-set +has_tracks;
test_capsule bundle paths +api/tracks). Additive; flagged for integration3 ratification.
Suite: 14 pre-existing files sum to 189 (floor held) + 20 new = 209 passed, exit 0.
Frontend `npm run build` clean. Do NOT merge — coordinator reviews + merges (DIRECTIVES R6 #3).
Recovered by the coordinator session after the foundation3 agent's isolation worktree was
removed mid-run, leaving the work uncommitted; every file independently reviewed, full suite +
build re-run green, then committed. No work redone.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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