E-00104: add headless agent visibility commands

[andrei-hasna]

Scope

Implements E-00104 under frozen acceptance scope tai-headless-agent-visibility-v1.

• Parent native plan: 8eadc06b-7276-4854-a6bc-b879866abf6f
• Parent goal: 32e0d30d-e05a-45ce-9034-dfc9afeefd1d
• Parent node: e7994834-cd3e-4416-80fc-9e82bb8b59e8
• Original implementation goal (provenance): d52a9bc4-9b80-47cd-8bb0-74e6797ee621
• Repair-cycle-1 goal: 50f30d4d-68d8-47cb-b95b-10e4b4b82f8c
• Final repair-cycle-2 goal: 69aba3b8-628f-4b7e-92fc-3b64c82d69ca
• Todos plan: a08dc545-512f-43ee-a553-6231a2131c50
• Owning task: 979b5c75-07d7-475d-9398-c4d17b1452d2 (E-00104)
• Writer generation: ae5c7772-13ae-4308-b514-735f0b42ff59
• Attempt nonce: 49517d66-fca3-4a56-91de-1470df659ce4
• Repair run: 03a59887-59f4-4dc0-baa0-d42864cf4c1d
• Risk tier: elevated
• Repair cycle count: 2 of 2
• Previous rejected head: 8b91c8deaa9289b216561ed192069fe141bc23e2
• CI prerequisite on main: 03b55df060fa034ad31a67fa14d35be81297f59c (E-00117 / PR ci: add provider-native validation workflow #4)
• Exact repaired head: 7ad8e0a1a53f6b1b238726e984298ec43184b751
• Remaining repair cycles after this handoff: 0

No third repair cycle is permitted. Any P0/P1/P2 finding in either fresh exact-head review makes this PR NO-GO for coordinator disposition.

Changed files

The cumulative PR diff remains exactly:

• README.md
• docs/architecture.md
• src/agents.ts
• src/cli/index.ts
• tests/agents.test.ts

Final repair

• The authenticated Todos /v1 GET surface is no longer called because current provider dispatch initializes schema before GET handling. Todos list and exact lookups return stable unavailable/incomplete evidence with zero provider operations; Codewith and Claude remain unavailable for the same side-effect-free proof boundary.
• Statuses use an explicit own closed set. Prototype names, unknown values, missing values, and invalid evidence fail closed.
• Printable IDs, assignment, task status, stale evidence, expired locks, and unassigned tasks do not prove live-agent provenance. A future Todos source must follow authoritative lease ownership and expiry semantics.
• Exact lookup rejects noncanonical uppercase UUIDs before provider execution.
• HTTP status, redirects, HTML 404s, malformed bodies, partial statuses, and arbitrary 201/206/226 responses cannot become complete or not-found.
• Timestamps accept only strict RFC3339 with an explicit timezone. Locale-dependent, invalid, absent, future, and unproven stale evidence fail closed.
• Timestamp-free dedupe and ordering continue through explicit status precedence and stable canonical tie-breakers without NaN.
• The reusable process boundary tracks descendants with start-time fencing and an inherited opaque scope, kills detached or reparented descendants, destroys retained pipes, and resolves within its bounded strategy. Current agent visibility invokes no provider process.
• The earlier IPv6 loopback enablement claim was removed. TODOS_URL, including http://[::1], is inert and fails closed consistently.

The surface remains stateless and omission-first. It does not expose provider-controlled titles, paths, branch data, tool text, goal text, credentials, account identifiers, URI query/fragment values, raw diagnostics, or terminal-control text. It creates no provider/config/database/cache/auth/task/lock/shadow WorkRun state.

Validation

• Regression artifacts: /tmp/e00104-review-1.json and /tmp/e00104-review-2.json replayed
• Regression-first red evidence: 7 accepted findings failed before product repair; follow-up hardening reproduced two timestamp/status failures and the reparented-grandchild escape before fixes
• bun test tests/agents.test.ts — 40 pass, 243 expectations
• Focused suite under UTC, Europe/Bucharest, and America/Los_Angeles — 40 pass in each timezone
• Detached-grandchild black-box subset — 2 pass across five repeated runs
• bun test — 56 pass, 290 expectations
• bun run typecheck — pass
• bun run build — pass
• Source JSON/human/exact/uppercase, built-package, and disposable-cwd smokes — pass
• Hostile environment/output leakage probe — pass
• git diff --check and exact five-file cumulative scope check — pass
• Labeled adversarial self-review — P0 none, P1 none, P2 none
• Staged, repair-range, and cumulative nonprinting redacted secret scans — pass
• Provider-native CI on exact repaired head — pass: https://github.com/hasna/tai/actions/runs/30027228735/job/89274658797
• Two fresh independent read-only exact-head reviews for repair count 2 — terminal FAIL; blocking findings remain

Rollback

Before merge, close this PR. After merge, revert the PR merge commit. No database, cache, provider state, lock, task, configuration, package, release, or deployment migration is involved.

Final exact-head review verdicts

Both fresh read-only reviewers were bound to PR #3, exact head 7ad8e0a1a53f6b1b238726e984298ec43184b751, acceptance scope tai-headless-agent-visibility-v1, and repair count 2.

• Reviewer /root/cycle2_review_a, run 9ccb2778-e2e6-4757-a6f4-0646567ff338: FAIL. P1 detached/reparented descendants can escape when an intermediate clears the inherited scope marker; P2 direct snapshot cleanup can SIGKILL a recycled unrelated PID without start-time validation.
• Reviewer /root/cycle2_review_b, run 9c0f7053-48b5-4266-a925-0cf17757d528: FAIL. P1 rapidly reparented marker-cleared descendants escaped in 44/80 probes; P1 direct snapshot cleanup lacks PID start-time validation; P2 canonical lowercase UUIDv6-v8 IDs are rejected by the version-1-through-5 validator.

No third repair cycle is permitted. This PR is NO-GO for coordinator disposition and remains open, unmerged, and preserved at the exact failed-review head.

[andrei-hasna]

Terminal NO-GO closure for E-00104 at exact failed head 7ad8e0a. Final exact-head FAIL reviewers: 9ccb2778-e2e6-4757-a6f4-0646567ff338 and 9c0f7053-48b5-4266-a925-0cf17757d528. Repair cap is exhausted at 2/2; no third repair cycle is permitted. Branch feat/e-00104-headless-agent-visibility is intentionally retained at the failed head.