docs: add concise documentation for issues 63 and 64 implementations

[senomorf]

Summary

Adds concise documentation covering critical gaps from error-driven limit detection (PR #69) and architecture-aware timeout handling (PR #70) implementations. All content optimized for minimal token count while maintaining completeness.

Documentation Updates

CLAUDE.md (Token-Optimized)

• ✅ Error Classification: Added USER_LIMIT_REACHED (exit code 5) with concise behavior
• ✅ Error-Driven Limit Detection: 4-line essential implementation covering 4,320+ API call savings
• ✅ Architecture-Aware Timeout Handling: 3-line core logic preserving capacity errors

docs/limits-management.md (New)

• ✅ Essential Commands: limit-status, check-limit, clear-limits, set-limit
• ✅ Free Tier Limits: E2 (2 max), A1 (4 OCPUs total)
• ✅ Key Behaviors: Exit codes, cache TTL, pre-flight checks

docs/troubleshooting.md (Minimal Addition)

• ✅ User Limit Troubleshooting: Exit code 5 handling (8 lines)
• ✅ Updated Validation: Added USER_LIMIT_REACHED to exit code tests

README.md (Concise Updates)

• ✅ Feature List: Added error-driven detection and timeout handling
• ✅ Documentation Reference: Added limits-management.md link

Key Benefits

• Closes documentation gaps for two major feature implementations
• Token-efficient approach - especially optimized CLAUDE.md for context usage
• Essential information only - removed verbose explanations, kept actionable content
• Maintains project consistency - follows existing documentation patterns

Coverage Analysis

Before: Missing documentation for:

• Error-driven limit detection behavior and commands
• New exit code 5 (USER_LIMIT_REACHED)
• Architecture-aware timeout handling improvements
• State manager limit management commands

After: Complete coverage with minimal token overhead

Implementation Details

• Zero API Overhead: Documents how limit detection learns from natural failures
• 24-Hour Cache TTL: Explains automatic limit state management
• Smart Shape Filtering: Pre-flight cache checks prevent futile attempts
• Timeout Race Condition Fix: Architecture-aware handling preserves error codes

Total addition: ~70 lines across 4 files, covering comprehensive feature documentation.