backlot phase 2: board UI (library, live board, filmstrip, script modal, drawers)

- vanilla ESM frontend on the mockup design system (no build step):
  library contact-sheet with mini rails + live badges; project board with
  slate header, cost meter, clickable stage rail, stage drawers (artifact
  view, review findings, gate-skipped chip, versions), screenplay card +
  full-script modal, decisions + activity rails, storyboard filmstrip
  (duration-width cards, shimmer/spec/missing/text-card states, takes,
  narration + waveform playback), render player with versions, degraded
  found-media view
- /thumb endpoint: cached downscaled JPEGs (Pillow) + ffmpeg poster-frame
  extraction for videos — the library was loading 73 full-res PNGs
- library summaries cached, invalidated by the watcher
- asset path resolution tolerates project-relative, repo-relative and
  absolute manifest paths (real-world variance found in why-do-we-dream)
- ?static=1 disables SSE (screenshots/static export)
- verified in browser against signal-from-tomorrow, why-do-we-dream,
  done-beats-perfect and the 73-project library

.claude/launch.json

@@ -0,0 +1,17 @@
+{
+  "version": "0.0.1",
+  "configurations": [
+    {
+      "name": "backlot",
+      "runtimeExecutable": "python",
+      "runtimeArgs": ["-m", "backlot", "serve", "--port", "4750"],
+      "port": 4750
+    },
+    {
+      "name": "mockups",
+      "runtimeExecutable": "python",
+      "runtimeArgs": ["-m", "http.server", "4788", "--bind", "127.0.0.1"],
+      "port": 4788
+    }
+  ]
+}