docs: add shared module map to CLAUDE.md, SECURITY.md, planning artifacts

- CLAUDE.md: add Code Standards section with backend and frontend shared
  module maps, component architecture rules, duplication checklist, and
  no-dead-code enforcement rule
- SECURITY.md: Phase 02 + 03 security audit results (all threats CLOSED)
- .planning: update milestone audit, config, and add plan/UAT files for
  phases 01, 02-06, and 06.2-05

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

.planning/config.json

@@ -13,7 +13,8 @@
     "test_gate": true,
     "security_check": true,
     "bugfix_max_lines": 50,
-    "require_root_cause_fix": true
+    "require_root_cause_fix": true,
+    "_auto_chain_active": false
   },
   "ship": {
     "pr_body_sections": [