fix(skills): replace sqlite3 CLI with in-tree better-sqlite3 wrapper

Setup deliberately avoids the sqlite3 CLI (`setup/verify.ts:5` calls
this out: "Uses better-sqlite3 directly (no sqlite3 CLI)") and never
installs or probes for the binary. Despite that, 13 skills shelled out
to `sqlite3 ...` directly, breaking on hosts where the CLI isn't
preinstalled — the same root cause as #2191 but spread across the
skill surface.

Add `scripts/q.ts`, a ~30-LOC wrapper over the `better-sqlite3` dep
that setup already installs and verifies. Default output matches
`sqlite3 -list` (pipe-separated, no header) so existing skill text
reads identically — only the binary changes. SELECT/WITH queries go
through `db.prepare().all()`; everything else (INSERT/UPDATE/DELETE,
including compound statements) goes through `db.exec()`.

Migrate every in-tree caller:

- 17 hardcoded invocations across 8 SKILL.md files (init-first-agent,
  add-deltachat, add-signal, add-emacs, add-whatsapp, add-ollama-provider,
  debug, add-parallel) plus add-deltachat/VERIFY.md.
- `manage-channels/SKILL.md` shows canonical SQL but never prescribed
  a tool, so the assistant defaulted to `sqlite3` and silently failed.
  Add a one-line wrapper hint above the SQL block.
- `migrate-v2.sh` schema/count probes (was the original #2191 case).
  Replace `.tables` with `SELECT name FROM sqlite_master`.
- Document the wrapper convention in root `CLAUDE.md` under "Central DB".

Add `scripts/q.test.ts` with 6 vitest cases covering both modes,
NULL rendering, empty-result, compound mutations, and arg validation.
Wire `scripts/**/*.test.ts` into `vitest.config.ts`.

Out of scope (flagged for follow-up):
- `debug` and `add-parallel` still reference the v1-only path
  `store/messages.db`. Routing through the wrapper now produces a
  cleaner "no such file" error, but the surrounding sections are
  v1-era throughout — a v1-content cleanup is its own PR.
- `cleanup-sessions.sh` is being addressed in #1889 (different style,
  hard-fail rather than wrap); left untouched here to avoid stepping
  on that author's work.

Closes #2191.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/q.ts

@@ -0,0 +1,46 @@
+/**
+ * scripts/q.ts — sqlite3 CLI replacement for skill SQL invocations.
+ *
+ * Usage:
+ *   pnpm exec tsx scripts/q.ts <db-path> "<sql>"
+ *
+ * Detects SELECT vs mutation on the first keyword. SELECT/WITH queries
+ * print rows in sqlite3 CLI default ("list") format — pipe-separated,
+ * no header — so existing skill text reads identically. Anything else
+ * runs through db.exec() and prints nothing on success.
+ *
+ * Why this exists: setup/verify.ts:5 codifies that NanoClaw avoids
+ * depending on the sqlite3 CLI binary; setup never installs or probes
+ * for it. Skills that shell out to `sqlite3` therefore fail on hosts
+ * where it isn't preinstalled (common on fresh Ubuntu — see #2191).
+ * This wrapper preserves the skill-text shape (path then SQL string)
+ * while routing through the better-sqlite3 dep that setup already
+ * installs and verifies.
+ */
+import Database from 'better-sqlite3';
+
+const [, , dbPath, sql] = process.argv;
+
+if (!dbPath || sql === undefined) {
+  console.error('Usage: pnpm exec tsx scripts/q.ts <db-path> "<sql>"');
+  process.exit(2);
+}
+
+const db = new Database(dbPath);
+try {
+  const firstKeyword = sql.trim().split(/\s+/)[0]?.toUpperCase() ?? '';
+  if (firstKeyword === 'SELECT' || firstKeyword === 'WITH') {
+    const rows = db.prepare(sql).all() as Record<string, unknown>[];
+    for (const row of rows) {
+      console.log(
+        Object.values(row)
+          .map((v) => (v === null ? '' : String(v)))
+          .join('|'),
+      );
+    }
+  } else {
+    db.exec(sql);
+  }
+} finally {
+  db.close();
+}