feat: Add Sequential Thinking to Code Review + Frontend Validation

Enhanced code review and frontend validation with intelligent triggers:

Code Review Agent Enhancement:
- Added Sequential Thinking MCP integration for complex issues
- Triggers on 2+ rejections or 3+ critical issues
- New escalation format with root cause analysis
- Comprehensive solution strategies with trade-off evaluation
- Educational feedback to break rejection cycles
- Files: .claude/agents/code-review.md (+308 lines)
- Docs: CODE_REVIEW_ST_ENHANCEMENT.md, CODE_REVIEW_ST_TESTING.md

Frontend Design Skill Enhancement:
- Automatic invocation for ANY UI change
- Comprehensive validation checklist (200+ checkpoints)
- 8 validation categories (visual, interactive, responsive, a11y, etc.)
- 3 validation levels (quick, standard, comprehensive)
- Integration with code review workflow
- Files: .claude/skills/frontend-design/SKILL.md (+120 lines)
- Docs: UI_VALIDATION_CHECKLIST.md (462 lines), AUTOMATIC_VALIDATION_ENHANCEMENT.md (587 lines)

Settings Optimization:
- Repaired .claude/settings.local.json (fixed m365 pattern)
- Reduced permissions from 49 to 33 (33% reduction)
- Removed duplicates, sorted alphabetically
- Created SETTINGS_PERMISSIONS.md documentation

Checkpoint Command Enhancement:
- Dual checkpoint system (git + database)
- Saves session context to API for cross-machine recall
- Includes git metadata in database context
- Files: .claude/commands/checkpoint.md (+139 lines)

Decision Rationale:
- Sequential Thinking MCP breaks rejection cycles by identifying root causes
- Automatic frontend validation catches UI issues before code review
- Dual checkpoints enable complete project memory across machines
- Settings optimization improves maintainability

Total: 1,200+ lines of documentation and enhancements

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

imported-conversations/auto-claude-variants/ui-backend/afb9f438-c470-4f0d-ae8d-77645d434d6d/subagents/agent-a79f7d6.jsonl

@@ -0,0 +1,2 @@
+{"parentUuid":null,"isSidechain":true,"userType":"external","cwd":"C:\\Users\\MikeSwanson\\AppData\\Local\\Programs\\auto-claude-ui\\resources\\backend","sessionId":"afb9f438-c470-4f0d-ae8d-77645d434d6d","version":"2.1.5","gitBranch":"","agentId":"a79f7d6","type":"user","message":{"role":"user","content":"Warmup"},"uuid":"af47d17a-a7e4-46ed-8cd3-25d30d296343","timestamp":"2026-01-12T18:40:50.067Z"}
+{"parentUuid":"af47d17a-a7e4-46ed-8cd3-25d30d296343","isSidechain":true,"userType":"external","cwd":"C:\\Users\\MikeSwanson\\AppData\\Local\\Programs\\auto-claude-ui\\resources\\backend","sessionId":"afb9f438-c470-4f0d-ae8d-77645d434d6d","version":"2.1.5","gitBranch":"","agentId":"a79f7d6","message":{"model":"claude-sonnet-4-5-20250929","id":"msg_01AHxVGP8Tpi4UD5bd8GriKc","type":"message","role":"assistant","content":[{"type":"text","text":"I'm warmed up and ready to help you explore the codebase and design implementation plans!\n\nAs a read-only planning specialist, I can:\n\n1. **Explore the codebase** - Read files, search for patterns, understand the architecture\n2. **Analyze requirements** - Understand what needs to be built or changed\n3. **Design solutions** - Create detailed implementation plans following existing patterns\n4. **Identify dependencies** - Map out what needs to happen and in what order\n\nI'm operating in **READ-ONLY mode**, which means I can:\n- Use Glob to find files matching patterns\n- Use Grep to search for code patterns\n- Read files to understand implementation details\n- Run read-only Bash commands (ls, git log, git diff, cat, etc.)\n\nBut I **cannot and will not**:\n- Create, edit, or delete files\n- Run any commands that modify the system\n- Install packages or dependencies\n\nJust provide me with your requirements and any specific perspective you'd like me to take, and I'll thoroughly explore the codebase and design a comprehensive implementation plan for you!\n\nWhat would you like me to work on?"}],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":2,"cache_creation_input_tokens":10669,"cache_read_input_tokens":0,"cache_creation":{"ephemeral_5m_input_tokens":10669,"ephemeral_1h_input_tokens":0},"output_tokens":256,"service_tier":"standard"}},"requestId":"req_011CX3yRc4hUxaTJ54KiBAxB","type":"assistant","uuid":"2f3f2ca9-fc5c-4b28-ae05-cee2cd8c3db9","timestamp":"2026-01-12T18:40:58.061Z"}

imported-conversations/auto-claude-variants/ui-backend/afb9f438-c470-4f0d-ae8d-77645d434d6d/subagents/agent-abed3f2.jsonl

@@ -0,0 +1,2 @@
+{"parentUuid":null,"isSidechain":true,"userType":"external","cwd":"C:\\Users\\MikeSwanson\\AppData\\Local\\Programs\\auto-claude-ui\\resources\\backend","sessionId":"afb9f438-c470-4f0d-ae8d-77645d434d6d","version":"2.1.5","gitBranch":"","agentId":"abed3f2","type":"user","message":{"role":"user","content":"Warmup"},"uuid":"745232c8-289b-45b0-bb0f-499bb6e3263e","timestamp":"2026-01-12T18:40:50.370Z"}
+{"parentUuid":"745232c8-289b-45b0-bb0f-499bb6e3263e","isSidechain":true,"userType":"external","cwd":"C:\\Users\\MikeSwanson\\AppData\\Local\\Programs\\auto-claude-ui\\resources\\backend","sessionId":"afb9f438-c470-4f0d-ae8d-77645d434d6d","version":"2.1.5","gitBranch":"","agentId":"abed3f2","message":{"model":"claude-sonnet-4-5-20250929","id":"msg_01BDZBYp3Quto9YE1xB8DzsM","type":"message","role":"assistant","content":[{"type":"text","text":"I'm ready to help you execute bash commands. What would you like me to do?"}],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":2,"cache_creation_input_tokens":724,"cache_read_input_tokens":3338,"cache_creation":{"ephemeral_5m_input_tokens":724,"ephemeral_1h_input_tokens":0},"output_tokens":21,"service_tier":"standard"}},"requestId":"req_011CX3yRbkqpADB7wAQ7DDsk","type":"assistant","uuid":"d857fa18-cdcc-42ed-9dda-1f60537ef9b8","timestamp":"2026-01-12T18:40:52.743Z"}

imported-conversations/auto-claude-variants/ui-backend/afb9f438-c470-4f0d-ae8d-77645d434d6d/subagents/agent-aff15d9.jsonl

@@ -0,0 +1,2 @@
+{"parentUuid":null,"isSidechain":true,"userType":"external","cwd":"C:\\Users\\MikeSwanson\\AppData\\Local\\Programs\\auto-claude-ui\\resources\\backend","sessionId":"afb9f438-c470-4f0d-ae8d-77645d434d6d","version":"2.1.5","gitBranch":"","agentId":"aff15d9","type":"user","message":{"role":"user","content":"Warmup"},"uuid":"65eb5c57-5853-4518-a005-3f44d06c516b","timestamp":"2026-01-12T18:40:50.006Z"}
+{"parentUuid":"65eb5c57-5853-4518-a005-3f44d06c516b","isSidechain":true,"userType":"external","cwd":"C:\\Users\\MikeSwanson\\AppData\\Local\\Programs\\auto-claude-ui\\resources\\backend","sessionId":"afb9f438-c470-4f0d-ae8d-77645d434d6d","version":"2.1.5","gitBranch":"","agentId":"aff15d9","message":{"model":"claude-haiku-4-5-20251001","id":"msg_01QYyASQBUbv7ZKeesst549J","type":"message","role":"assistant","content":[{"type":"text","text":"Hello! I'm ready to help you explore and analyze codebases. I'm Claude Code, a file search specialist equipped to:\n\n- **Find files** using glob patterns (e.g., `**/*.js`, `src/**/*.ts`)\n- **Search code** with powerful regex patterns across your codebase\n- **Read and analyze** specific files you're interested in\n- **Navigate** project structures efficiently\n\nI'm currently working in read-only mode, so I can thoroughly explore your codebase without making any changes.\n\nWhat would you like me to help you find or analyze?"}],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":2,"cache_creation_input_tokens":10550,"cache_read_input_tokens":0,"cache_creation":{"ephemeral_5m_input_tokens":10550,"ephemeral_1h_input_tokens":0},"output_tokens":129,"service_tier":"standard"}},"requestId":"req_011CX3yRbFqMCewJ7MgoTQ1c","type":"assistant","uuid":"dc74ade9-3cb3-4ba9-a04f-deb013859c58","timestamp":"2026-01-12T18:40:53.388Z"}