Merge remote-tracking branch 'origin/main' into garrytan/askuser-one-at-a-time

Resolved conflicts:
- scripts/gen-skill-docs.ts: kept both sides (empty conflict at section boundary)
- VERSION: bumped to 0.11.13.1 (our MICRO on top of main's 0.11.13.0)
- CHANGELOG.md: added our 0.11.13.1 entry above main's 0.11.13.0
- SKILL.md files: regenerated from resolved templates via bun run gen:skill-docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

retro/SKILL.md

@@ -1,5 +1,6 @@
 ---
 name: retro
+preamble-tier: 2
 version: 2.0.0
 description: |
   MANUAL TRIGGER ONLY: invoke only when user types /retro.

retro/SKILL.md.tmpl

@@ -1,5 +1,6 @@
 ---
 name: retro
+preamble-tier: 2
 version: 2.0.0
 description: |
   Weekly engineering retrospective. Analyzes commit history, work patterns,