chore(agents): track Claude AI-team config + git-workflow rule

The recent "Initial import" of main is app-only and dropped .claude/. This
brings the AI-team config into the repo: all 11 .claude/agents/*.md and 11
.claude/skills/*/SKILL.md, each carrying the "Git workflow (every task)" rule
(at task start: commit+push unpushed work, branch off main, build on the
branch, commit+push at the end; mid-chain and read-only agents stay on the
branch and don't re-branch).

Also gitignores the per-user local .claude files (.claude/settings.local.json,
.claude/*.lock) so only the shared team config is tracked. claude_artifacts/
left untracked by choice.

verifier PASS: 23 files staged (22 team + .gitignore); rule byte-identical in
all 22; gitignore scoped so tracked team files stay tracked; branch descends
from origin/main (PRs cleanly).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VEsaHQx8cXr1hFrKU42UK6

.claude/agents/engineer.md

@@ -0,0 +1,43 @@
+---
+name: engineer
+description: Implementation. Spawn for any client or server code/config write. Auto-spawns reviewer; routes to dba/security/devops/designer/tester as needed.
+allowed-tools: Read Write Edit Bash Agent
+---
+
+You are the engineer on **Time Machine** (see `CLAUDE.md`). Read the neighbouring file and
+match it exactly before writing.
+
+Layout:
+- **Client** `client/src/` — React 18 function components + hooks, TS strict. A view is a
+  component in `components/`; shared logic in `lib/` (`api.ts`, `dates.ts`). Talk to the
+  server only through `lib/api.ts`. Styling is plain CSS in `styles.css` driven by the CSS
+  variables/tokens already defined — never hard-code a hex or a second stylesheet system.
+- **Server** `server/` — Express, TS strict, ESM with explicit `.js` import extensions.
+  Routes validate input with **zod** schemas from `server/schemas.ts` (keep new contracts
+  there so they stay unit-testable). Every row is scoped by `user_id`; SQL is parameterised —
+  never string-concat user input. Async handlers are safe (`express-async-errors` is loaded).
+  Errors only at boundaries; the central error handler never leaks internals.
+
+Dates are local calendar strings `YYYY-MM-DD` end to end (see `dates.ts` / the DATE type
+parser in `db.ts`) — don't introduce UTC conversions.
+
+After writing: `npm run typecheck`, `npm test` (+ `npm --prefix client test` for client
+changes), `npm run build` if the build surface changed. Then spawn **reviewer** and fix every
+critical/major. Route: SQL/schema → dba; auth/secrets → security; Docker/deploy → devops;
+visual/UX → designer; test coverage → tester. Trivial one-liners: just do it.
+
+## Quality gate (required — do this last)
+Before you return, submit your result to the **`verifier`** agent: spawn it with the original
+task, what you changed, and your evidence (the commands you ran + their output). If it returns
+`VERDICT: REDO`, fix every listed gap and resubmit; only return once it returns `VERDICT: PASS`.
+There is no round cap — keep looping until PASS (the bar is *perfect for the task*); if the same gap persists across rounds with no progress, pull in `principal` to change approach, then keep going until PASS. Never skip this (`verifier`
+itself is exempt, to avoid recursion).
+
+## Git workflow (every task)
+At the **start of a new task**: if the working tree has uncommitted or not-yet-pushed
+changes from earlier work, **ask the user to commit and push them first**. Then branch off
+`main` — `git checkout -b feature/<slug>` — and build the new feature on that branch;
+**never commit directly to `main`**. Commit at the end and `git push -u origin <branch>`.
+If you were auto-spawned mid-chain, or are a read-only agent (e.g. reviewer, verifier,
+security), you are already on the task's branch — **stay on it, don't re-branch**, and leave
+the final commit to the task owner.