Represent deployed builds and deployment evidence on tasks

[witbrock]

Tasks can now identify the deployed build that delivers their work, inspect deployment attempts and status receipts, and select a verified deployment as the current work product. The implementation adds separate build/deployment/observation concepts, canonical task links, authenticated receipt ingestion and traversal APIs, and task-panel history. Identical retries reuse records; conflicting evidence is rejected; rollback preserves attempt history.

The producer contract and scoped vocabulary activation procedure are documented in docs/engineering/deployment_evidence.md. Recording evidence does not deploy code or complete tasks; future producers explicitly submit receipts.

Validation:

• Original candidate: 43 targeted backend tests and 8 frontend tests passed.
• Current-main integration: 31 targeted deployment/work-product backend tests and 8 task-panel frontend tests passed; both required CI checks passed.
• A generation-disabled authenticated candidate with a disposable database ingested the real DGX restart receipt. Exact retries, all three traversal APIs and work-product selection passed canonical read-back.
• Authenticated browser checks at 1440/390 pixels rendered the real receipt, source revision and verified status, selected the work product, and showed no card overflow or JavaScript errors. These are simulated viewport checks, not physical-device testing.

Explicitly authorised DGX deployment completed at 2026-09-13T16:06:35Z on merge revision 30dc27b. Local and authenticated Cloudflare health agreed on PID 2777950; runtime was clean, database/worker/scheduler ready, and served taskPanel.js/styles.css matched. The database target and Jira migration service were preserved. Scoped vocabulary and the first real production receipt were canonically read back, including idempotent retry and the task's selected deployment work product. The unchanged startup workflow-purity advisory remains non-blocking.

Von task #V#task_agent_8f35430789702d95864e5def732c43cd is completed. Production deployment record: #V#deployment_50975745e20a5711195792dea8e1605762796e525b8851825030a83790faa845. Operator evidence is retained outside Git under /home/mjw/.codex-von-worker/build-tracking-acceptance-20260913/. The temporary acceptance server has been stopped.