Phase 2.3: Configuration Consolidation

# Phase 2.3: Configuration Consolidation
Week: 2 | Duration: 0.5 days | Status: ✅ Complete

## Objective
Merge `dlm/response/config.py` and `ircp/utils/config.py` into unified `dlm/config.py`

## Tasks
- [x] Merge ResponseConfig + IRCP config into DLMConfig
- [x] Add training configuration section
- [x] Add embedding configuration
- [x] Add coordinate calculation config
- [x] Support environment variables
- [x] Create config presets (dev/prod/performance/quality/coordinate-focus/conservation-focus)
- [x] Add validation with dataclasses
- [x] Add tests (20+ test cases)
- [x] Document configuration options (comprehensive guide)

## Files Created/Modified
- Created: `packages/dlm/config.py` (500+ lines)
- Created: `packages/dlm/tests/test_config.py` (comprehensive tests)
- Created: `packages/dlm/CONFIG_GUIDE.md` (complete documentation)
- Modified: `packages/dlm/response/config.py` (deprecation warning)

Implementation Summary

Successfully consolidated configuration from DLM, IRCP, and TPO:
1. Created unified `DLMConfig` with 13 configuration sections:
- TokenConfig, CoordinateConfig, IRCPConfig
- EmbeddingConfig, ModelConfig, TrainingConfig
- ContextArchivalConfig, ContextReorderingConfig, SynthesisTechniqueConfig
- DatabaseConfig, EvaluationConfig, LoggingConfig, ResourceConfig

2. Added 6 specialized presets:
- `create_default()` - Standard configuration
- `create_development()` - Fast iteration, DEBUG logging
- `create_performance_optimized()` - Speed over quality
- `create_quality_optimized()` - Quality over speed
- `create_production()` - Balanced for production
- `create_coordinate_focus()` - Optimized for coordinate accuracy
- `create_conservation_focus()` - Emphasizes conservation laws

3. Implemented file I/O:
- `from_file(path)` - Load from YAML or JSON
- `to_file(path)` - Save to YAML or JSON
- `from_dict(dict)` - Create from dictionary
- `to_dict()` - Convert to dictionary

4. Added environment variable support:
- `from_env(prefix="DLM_")` - Load from environment
- Format: `DLM_<SECTION>_<PARAMETER>`
- Example: `DLM_EMBEDDING_CACHE_CAPACITY=1024`

5. Deprecated old config:
- Added deprecation warning to `dlm/response/config.py`
- Maintained backward compatibility
- Clear migration path documented

6. Created comprehensive tests:
- 20+ test cases covering all features
- Preset validation
- File I/O round-trip testing
- Environment variable loading
- Backward compatibility checks

7. Wrote complete documentation:
- CONFIG_GUIDE.md with examples and best practices
- Quick start guide
- Section-by-section reference
- Migration guide from old config
- Troubleshooting section

Key technical decisions:
- Used dataclasses instead of Pydantic (simpler, stdlib)
- Support both YAML and JSON for flexibility
- Environment variables for deployment configuration
- Preset system for common scenarios
- Full backward compatibility

All acceptance criteria met. Ready to proceed to Phase 2.4.

Started: 2025-12-07
Completed: 2025-12-07
Time Spent: ~30 minutes

Next: [Phase 2.4: Logging Unification](PHASE_2_4_LOGGING.md)