feat: annotation and pre-label are per job, and the gallery is an accordion of jobs

[JArmandoAnaya]

What changed

The annotation job becomes the unit a person enters and the unit a model pre-labels, and the batch gallery shows a batch's frames one job at a time.

Pre-label is a job operation. POST /jobs/{job_id}/pre-label queues one annotation.pre_label row for one job (202 with a Location header, the contract the batch route had), keyed by annotation_job_id beside batch_id in the row's payload. POST /batches/{id}/pre-label and POST /projects/{id}/batches/pre-label stay, as fan-outs over each batch's open jobs, answering PreLabelFanOutOut — one row per job with annotation_job_id, the queued or joined background job, and joined. A finished job is passed over by a fan-out and refused by the job route (409 JOB_FINISHED). JobOut.pre_label_run remembers a job's newest run; BatchOut.pre_label_run is the newest across its jobs. The kernel declares JobAction.PRE_LABEL on an open job of an in_annotation batch (JOB_GATES, on BatchAction.PRE_LABEL's precedent); the CLI gains visionset job pre-label and the MCP server pre_label_job, and the batch and project verbs of both report one outcome per job. The plan stays batch-addressed — GET /batches/{id}/pre-label — because it is a property of the batch's pin and the model. A queue row enqueued before annotation_job_id existed is skipped by readers and fails its worker with a sentence saying why.

The gallery enters by job. The header carries Start annotating only for an approved batch — the approved → in_annotation transition, without an icon. Once a batch is open, the gallery is an accordion of its jobs (JobPanels.tsx): at most one panel is open, every panel may be closed, and the panel open on arrival is the first job with work left. A collapsed header states Job N · F frames · state · A of F annotated · assignee with a progress bar; the open panel carries the door (Annotate takes a pending job to in_progress and opens it; Continue and View only open), Pre-label gated on the job's allowed_actions, the assignee, segment chips counted from GET /jobs/{id}/progress, the order select, that job's timeline and only that job's frames, read through the new job filter on GET /batches/{id}/assets (BatchService.asset_page(job=), also on the MCP list_batch_assets). The thumbnail-size control is one shared setting on the header's caption line. A draft batch keeps the flat grid and its membership tools. The project's Annotate control opens a batch's one job directly and the gallery otherwise; the dropdown stays batch-level. The virtualised grid, selection and bulk bar moved unchanged into FrameGrid.tsx; JobsStrip/JobRow are gone.

Docs and rules. docs/content/ (batches, jobs, api, background-jobs, cli, mcp, ui, inference, architecture/backend/jobs) describe the job as the unit; mcp-tools.md, openapi.json, the generated client and the wire fixtures are regenerated. The batch-lifecycle skill's decision 10 now names a job-level pre-label action; the information-architecture skill records that Annotate enters by job and that a batch with jobs shows one job's frames at a time.

Found, not fixed

• JobPanels.tsx and GalleryScreen.tsx import each other (Toolbar, Timeline, StartJobButton still live in the screen module). Inert today — only hoisted function declarations cross the edge — and the fix is to move those three into their own module.
• A collapsed panel's header names an aria-controls id that is not mounted; the panel is unmounted rather than hidden so its filter and selection reset on switch.
• BatchOut.of keeps a pre_label_run=None default; JobOut.of no longer has one.

Test plan

• uv run pytest tests/kernel tests/inference tests/jobs tests/server tests/cli tests/mcp tests/architecture — green (the documented-refusals gate included)
• uv run mypy src/visionset (175 files), uv run lint-imports (4/4), uv run ruff check . && uv run ruff format --check .
• scripts/export_openapi.py, pnpm generate:client:check, scripts/export_wire_fixtures.py, scripts/export_mcp_tools.py --check — no drift
• pnpm -r build && pnpm -r test && pnpm -r lint — annotator 1071, ui-core 1331, app 11
• Playwright gallery, project-nav, annotate, navigation, viewport, visual; pnpm cycle (real server: approve → open the job from its panel → annotate → back reads in progress/Continue)
• CI: the full matrix, including the browser cycle job