Update docs, skill counts, and UX/setup-engine skills for v0.4.0

- Update skill count to 66 and hook count to 12 across README, skills-reference, and badges
- Add QA & Testing section to README and skills-reference (qa-plan, smoke-check, soak-test, etc.)
- Add Input & Platform section to technical-preferences.md (populated by /setup-engine)
- Document post-compact, notify, and validate-skill-change hooks in hooks-reference
- Expand /setup-engine, /ux-design, /ux-review, /design-system skills with input/platform context
- Restructure workflow-catalog: move UX steps into pre-production phase, improve descriptions
- Expand UPGRADING.md and WORKFLOW-GUIDE.md with v0.4.0 guidance
- Add skill-flow-diagrams examples and CODEOWNERS

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

.gitignore

@@ -11,14 +11,13 @@ Desktop.ini
 
 # === Claude Code Local ===
 .claude/settings.local.json
-.claude/docs/UPGRADE-PLAN.md
 CLAUDE.local.md
 production/session-logs/
 production/session-state/*.md
 
 # === Internal Planning (not for public) ===
-docs/IMPROVEMENTS-PROPOSAL.md
-docs/MULTI-STAGE-DOCUMENT-WORKFLOW.md
+
+expansions/
 
 # === Build Output ===
 build/