chore: dev loop prompt rewrite + branch safety + tox conventions

- timmy-loop-prompt.md: full rewrite (76→209 lines) with PR-only workflow,
  tox environments, git hooks, Kimi dispatch safety block, conventional commits
- kimi-code skill: added Branch & Convention Safety section
- memories/MEMORY.md: updated with branch protection notes
- config.yaml: removed dead kimi API key
- cron/jobs.json: updated scheduled jobs
- channel_directory.json: minor update
- .gitignore: exclude queue/ and *.db

.gitignore

@@ -58,5 +58,11 @@ bin/*
 !bin/timmy-tmux.sh
 !bin/timmy-watchdog.sh
 
+# ── Queue (transient task queue) ─────────────────────────────────────
+queue/
+
+# ── Database files (ephemeral, regeneratable) ────────────────────────
+*.db
+
 # ── OS junk ──────────────────────────────────────────────────────────
 .DS_Store