merge: integrate origin/main (v0.4.0, v0.4.1) into team-supabase-store

Resolves conflicts in CHANGELOG.md (ordering), CONTRIBUTING.md (eval
tools list merge), VERSION (take main's 0.4.1), qa/SKILL.md.tmpl
(keep full methodology + baseline line), eval-store.test.ts (drop
redundant comment).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

retro/SKILL.md.tmpl

@@ -13,7 +13,7 @@ allowed-tools:
   - AskUserQuestion
 ---
 
-{{UPDATE_CHECK}}
+{{PREAMBLE}}
 
 # /retro — Weekly Engineering Retrospective