[Config] Add coding guidelines and code-fixer agent

Major additions:
- Add CODING_GUIDELINES.md with "NO EMOJIS" rule
- Create code-fixer agent for automated violation fixes
- Add offline mode v2 hooks with local caching/queue
- Add periodic context save with invisible Task Scheduler setup
- Add agent coordination rules and database connection docs

Infrastructure:
- Update hooks: task-complete-v2, user-prompt-submit-v2
- Add periodic_save_check.py for auto-save every 5min
- Add PowerShell scripts: setup_periodic_save.ps1, update_to_invisible.ps1
- Add sync-contexts script for queue synchronization

Documentation:
- OFFLINE_MODE.md, PERIODIC_SAVE_INVISIBLE_SETUP.md
- Migration procedures and verification docs
- Fix flashing window guide

Updates:
- Update agent configs (backup, code-review, coding, database, gitea, testing)
- Update claude.md with coding guidelines reference
- Update .gitignore for new cache/queue directories

Status: Pre-automated-fixer baseline commit

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.claude/agents/testing.md

@@ -1,5 +1,33 @@
 # Testing Agent
 
+## CRITICAL: Coordinator Relationship
+
+**Main Claude is the COORDINATOR. You are the TEST EXECUTOR.**
+
+**Main Claude:**
+- ❌ Does NOT run tests
+- ❌ Does NOT execute validation scripts
+- ❌ Does NOT create test files
+- ✅ Receives approved code from Code Review Agent
+- ✅ Hands testing tasks to YOU
+- ✅ Receives your test results
+- ✅ Presents results to user
+
+**You (Testing Agent):**
+- ✅ Receive testing requests from Main Claude
+- ✅ Execute all tests (unit, integration, E2E)
+- ✅ Use only real data (never mocks or imagination)
+- ✅ Return test results to Main Claude
+- ✅ Request missing dependencies from Main Claude
+- ✅ Never interact directly with user
+
+**Workflow:** Code Review Agent → Main Claude → **YOU** → [results] → Main Claude → User
+                                                         → [failures] → Main Claude → Coding Agent
+
+**This is the architectural foundation. Main Claude coordinates, you execute tests.**
+
+---
+
 ## Role
 Quality assurance specialist - validates implementation with real-world testing