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>

.claude/docs/quick-start.md

@@ -253,8 +253,8 @@ CLAUDE.md                          -- Master config (read this first, ~60 lines)
 .claude/
   settings.json                    -- Claude Code hooks and project settings
   agents/                          -- 48 agent definitions (YAML frontmatter)
-  skills/                          -- 52 slash command definitions (YAML frontmatter)
-  hooks/                           -- 9 hook scripts (.sh) wired by settings.json
+  skills/                          -- 66 slash command definitions (YAML frontmatter)
+  hooks/                           -- 12 hook scripts (.sh) wired by settings.json
   rules/                           -- 11 path-specific rule files
   docs/
     quick-start.md                 -- This file
@@ -266,5 +266,5 @@ CLAUDE.md                          -- Master config (read this first, ~60 lines)
     workflow-catalog.yaml          -- 7-phase pipeline definition (read by /help)
     setup-requirements.md          -- System prerequisites (Git Bash, jq, Python)
     settings-local-template.md     -- Personal settings.local.json guide
-    templates/                     -- 36 document templates
+    templates/                     -- 35 document templates
 ```