docs: Add Phase 2 performance optimization plan and roadmap

Create comprehensive planning documentation for the next phase of
performance optimizations following successful Phase 1 list copy
optimizations (40-79% improvement achieved).

DOCUMENTATION ADDED:

1. Advanced Optimization Plan (.claude/rules/empathy/advanced-optimization-plan.md)
   - 4-track optimization strategy (profiling, generators, data structures, caching)
   - Week-by-week implementation roadmap
   - Profiling infrastructure setup guide
   - Code examples and migration patterns
   - Success metrics and monitoring approach

2. Performance Optimization Roadmap (docs/PERFORMANCE_OPTIMIZATION_ROADMAP.md)
   - High-level overview of optimization journey
   - Phase 1 results summary and benchmarks
   - Phase 2 targets and timeline
   - Tools and infrastructure requirements
   - Quick reference links

PHASE 2 OPTIMIZATION TRACKS:

Track 1: Profile Hot Paths (Priority: HIGH)
- Data-driven bottleneck identification
- cProfile, memory_profiler, py-spy, snakeviz
- Target: 5 high-frequency operations
- Tools: Profiling test suite, visualization

Track 2: Generator Expression Migration (Priority: MEDIUM)
- Replace memory-intensive list comprehensions
- Target: One-time iterations, large datasets
- Expected: 50%+ memory reduction
- Pattern: File scanning, log processing, pattern matching

Track 3: Data Structure Optimization (Priority: MEDIUM)
- Replace O(n) lookups with O(1) hash lookups
- Add index structures to Pattern Library and File Index
- Target: Lookup-heavy operations
- Expected: >50% speedup

Track 4: Intelligent Caching (Priority: HIGH)
- Cache expensive computations (>10ms)
- File hashing, AST parsing, pattern matching, API responses
- LRU cache with monitoring
- Expected: 60-80% cache hit rates

TIMELINE:
- Week 1 (Jan 13-17): Profiling & Analysis
- Week 2 (Jan 20-24): High-Priority Optimizations
- Week 3 (Jan 27-31): Caching & Validation

SUCCESS METRICS:
- Project scan: 5.2s → 3.0s (target) / 2.0s (stretch)
- Pattern matching: 850ms → 500ms / 300ms
- Memory usage: 120MB → 80MB / 60MB
- Cache hit rate: 0% → 60% / 80%

FILES ADDED: 2 comprehensive planning documents

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

Author: silversurfer562