docs: richer report — data figures, success/failure frames, commit-pinned repo links

- experiment_charts.py generates 4 figures from experiments/ artifacts:
  held-out per-film F1, 16-combo ranking, DE search landscape, and the
  Downton detector-vs-tracker ghost timeline (replaces the blank
  title-card screenshot)
- new frames: 19-correct wedding shot (success case), Many Saints
  ghost-vs-unknown frame (three error classes in one image)
- rename rep4-optimizer-results.md -> model-bakeoff.md; rep4 kept only
  as the on-disk artifact prefix, explained once
- repo file references are now links via https://REPOLINK/<path>
  placeholders; build_site.sh pins them to the HEAD commit's raw URLs
  and fails the build if a linked path doesn't exist at HEAD
- drop references to removed scripts (scene_score.py, score_config.py)
  and to session-memory names; mark artifact-registry paths with their
  pull commands
- commit readme_example.jpg + pipeline_topology.svg so README renders
  on the plain Gitea repo view
- deploy_pages.sh: push built site/ to the gitea-pages branch

docs/index.md

@@ -5,6 +5,16 @@ film or TV episode — built on [KPN++](https://gitea.tourolle.paris/dtourolle/K
 (a C++20 Kahn Process Network library) for the detect → track → match → scene
 pipeline, with a Jellyfin-integrated gallery and an X-Ray-validated optimizer.
 
+This is what a good second looks like — one sampled frame from a held-out film,
+19 faces named, all 19 correct, the rest honestly declared unknown:
+
+![19 correct identifications in one wedding shot, Downton Abbey: A New Era](assets/images/downton_wedding_19_correct.jpg)
+
+And this is why the work isn't done: on this same film the same config misses
+6 in 10 of the actor-seconds X-Ray says are present, and on the worst held-out
+film it reports ghost actors over empty walls — at 100% confidence. Both
+stories, with the evidence, are in the pages below.
+
 ## Start here — four questions this bake-off answers
 
 - **[Which model is best?](best-model.md)** — calibration curves first
@@ -24,14 +34,14 @@ pipeline, with a Jellyfin-integrated gallery and an X-Ray-validated optimizer.
 
 ## The full technical log
 
-- **[Rep4 model bake-off + threshold re-tune](rep4-optimizer-results.md)** —
+- **[Model bake-off + threshold re-tune](model-bakeoff.md)** —
   the complete experiment log behind the four pages above: the ROCm teardown
   deadlock root cause and fix, DE concurrency tuning, the full 16-combo
-  results table, and every caveat. This is where the shipped `src/config.hpp`
-  defaults come from.
+  results table, and every caveat. This is where the shipped
+  [`src/config.hpp`](https://REPOLINK/src/config.hpp) defaults come from.
 - **[Optimizer experiments (prior round)](optimizer-experiments.md)** — the
   earlier scene-union-metric tuning pass, superseded by the per-second metric
-  used in rep4 but kept for the ground-truth/architecture background.
+  used in the bake-off but kept for the ground-truth/architecture background.
 - **[Service conversion (proposal)](service-conversion.md)** — design sketch
   for an idle-GPU Docker worker, not yet built.
 
@@ -47,5 +57,5 @@ scripts/artifacts/pull_artifacts.sh experiment-data
 scripts/artifacts/pull_artifacts.sh montage-frames <film-slug>
 ```
 
-See `scripts/artifacts/push_artifacts.sh` for the upload side (requires a
-`GITEA_TOKEN` with package write scope).
+See [`scripts/artifacts/push_artifacts.sh`](https://REPOLINK/scripts/artifacts/push_artifacts.sh)
+for the upload side (requires a `GITEA_TOKEN` with package write scope).