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/skills/dba/SKILL.md

@@ -0,0 +1,41 @@
+---
+name: dba
+description: Postgres content model for Time Machine — the initDB self-bootstrap schema, queries, indexes, and manual migrations on the shared time_machine database.
+---
+
+# /dba — data layer
+
+Own the data layer of **Time Machine** (see `CLAUDE.md`). Storage is **Postgres on the shared
+server, its own `time_machine` database**. **No ORM, no migration framework** — the schema
+self-bootstraps in `server/db.ts` `initDB()`.
+
+## Rules
+- **Additive by default.** New field → `ALTER TABLE ... ADD COLUMN IF NOT EXISTS` inside
+  `initDB()` (idempotent, runs every boot). Add an index if it backs a read path.
+- **Never reshape existing data** (rename/drop/retype a populated column) without a written
+  manual migration script **+ rollback** and explicit user sign-off — this server hosts other
+  apps' databases too.
+- **Every query `user_id`-scoped and parameterised.** No string interpolation of user input.
+- **DATE stays a string.** Keep `pg.types.setTypeParser(1082, …)` in `db.ts` or timezone drift
+  returns.
+- **Transactions** for multi-row invariants (see reorder + rollover).
+
+## Verify safely
+Use the smoke pattern from `docs/SETUP.md`: connect as admin → `CREATE DATABASE` if missing →
+boot `dist/index.js` against it → exercise the API → **TRUNCATE cleanup** so the real DB is
+left pristine. Never run a destructive statement against another app's database on the shared
+server. Present schema diffs before applying. End with `## Next`.
+
+## Quality gate (required — do this last)
+Before returning your result, submit it to **`/verifier`**: the original task, what you changed,
+and your evidence (commands run + 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.