feat(trainer): training from the collector UI — the trainer becomes a job service, the review page gains a Training section

Trainer: `parking-trainer serve` — a stdlib HTTP job API on the compose network (never
published): /health, /readiness, /versions, /versions/<v>/report, /jobs. One job at a
time; each job runs the CLI as a subprocess with its output captured, state + log
persisted under /out/jobs/ so a restart keeps history. `publish` takes its URL from
TRAINER_PUBLISH_URL. Dockerfile: CMD serve, EXPOSE 8091, healthcheck.

Collector: COLLECTOR_TRAINER_URL + /api/training/{status,jobs,jobs/:id,versions/:v/report}
— a reviewer-gated proxy that forwards a fixed set of paths and whitelisted knobs and
passes the trainer's status codes through (409 while a job runs; 503 unconfigured, 502
unreachable). /review gains the Training section: labels per class vs the minimum with
Train disabled until two classes clear it, mode / backbone / floor, the running job's
live log, the versions with Report / Evaluate / Publish (publish confirms), and the
reminder that pinning stays a git commit. Fixed on the way: an apostrophe in the page's
inline script broke the whole page — a test now parses the script.

Compose: `trainer` is a service (restart: unless-stopped, read-only data volume, its own
trainer-out volume), the `train` profile and TRAINER_OUT are gone; the Docker-socket
route was rejected (root on the host for a service booths upload to). Verified with both
images running together: a Train started through the proxy finished, version and report
came back, the page rendered.

Wiki: bodytype-classifier-training (loop, running it, operating notes superseded),
vision-review-outbox, fleet-deployment-komodo, log.

Claude-Session: https://claude.ai/code/session_01FWncR69HgGPuei1dLrW3cU

wiki/log.md

@@ -3144,6 +3144,20 @@ run; the Quadro FX 3800 is unusable (cc 1.3), the HD P530 irrelevant, the Xeon E
 compose seam drops the GPU reservation; cloud GPU rejected (crops stay on premises). Linked from
 [[opencv-anpr-service]], [[vision-review-outbox]], index. User: "No build just yet."
 
+## [2026-09-07] build | Training from the collector UI — the trainer becomes a job service
+User: the compose-profile trainer is "not so smart" (where is the compose file on a periphery
+host? why not a button on the collector UI?). Built: `parking-trainer serve` — a stdlib job API
+(`/health`, `/readiness`, `/versions`, `/versions/<v>/report`, `/jobs`), one job at a time, each
+job the CLI as a subprocess with state + log persisted under `/out/jobs/`; the collector gained
+`COLLECTOR_TRAINER_URL` + `/api/training/*` (reviewer-gated proxy, fixed paths, whitelisted
+knobs, trainer status codes passed through, 503 unconfigured / 502 unreachable) and a Training
+section on `/review` (readiness table, Train with mode/backbone/floor, live log, versions with
+Report / Evaluate / Publish, the pin reminder). Compose: `trainer` is a service now
+(`restart: unless-stopped`, `serve`, read-only data, own `trainer-out` volume, not published);
+the Docker socket route was rejected (root on the host for a service booths upload to). Tests:
+trainer 14, collector 7. Pages: [[bodytype-classifier-training]] (loop, running it, operating
+notes superseded), [[vision-review-outbox]], [[fleet-deployment-komodo]].
+
 ## [2026-09-07] ingest | Trainer deployed as a profile; operating notes
 User pushed `stage-f7a262a`, bumped the `wash-collector` TAG, redeployed, and asked why only one
 service runs on art-docker-station. Expected: the trainer is a compose profile, never started or