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/autocode-remix-fork/agent-a627cc1.jsonl

@@ -0,0 +1,2 @@
+{"parentUuid":null,"isSidechain":true,"userType":"external","cwd":"C:\\Users\\MikeSwanson\\claude-projects\\Autocode-remix\\Autocode-fork","sessionId":"a29f3a47-c4a7-4f35-b421-b785db185bdb","version":"2.1.1","gitBranch":"main","agentId":"a627cc1","type":"user","message":{"role":"user","content":"Warmup"},"uuid":"d5018969-d8ae-4312-892c-8ad2a94b67b5","timestamp":"2026-01-08T21:39:01.232Z"}
+{"parentUuid":"d5018969-d8ae-4312-892c-8ad2a94b67b5","isSidechain":true,"userType":"external","cwd":"C:\\Users\\MikeSwanson\\claude-projects\\Autocode-remix\\Autocode-fork","sessionId":"a29f3a47-c4a7-4f35-b421-b785db185bdb","version":"2.1.1","gitBranch":"main","agentId":"a627cc1","message":{"model":"claude-haiku-4-5-20251001","id":"msg_01C5G7RzfkehTdgSE9B4EZ4A","type":"message","role":"assistant","content":[{"type":"text","text":"I'm ready to help you explore and analyze code in the Autocode-remix/Autocode-fork project. I understand my role and constraints:\n\n**Key points I'm following:**\n- **READ-ONLY MODE**: I can search and analyze, but cannot create, modify, or delete files\n- **My tools**: Glob for file patterns, Grep for content search, Read for specific files, Bash for read-only operations\n- **Context awareness**: I'll check session logs and credentials.md as needed\n- **Efficiency**: I'll make parallel tool calls when possible to search quickly\n\nI'm familiar with your infrastructure, projects, and the CLAUDE.md guidelines. \n\nHow can I help you explore the codebase today?"}],"stop_reason":"end_turn","stop_sequence":null,"usage":{"input_tokens":3,"cache_creation_input_tokens":11982,"cache_read_input_tokens":0,"cache_creation":{"ephemeral_5m_input_tokens":11982,"ephemeral_1h_input_tokens":0},"output_tokens":163,"service_tier":"standard"}},"requestId":"req_011CWvdnFnnLqpRZoU3abdeM","type":"assistant","uuid":"b8ca2a1f-06b6-46fe-9883-64496f2de878","timestamp":"2026-01-08T21:39:08.279Z"}