feat(ai): complete Phase 2/3 documentation and memory system improvements

Phase completion and enhancement updates:

## Documentation Added
- Phase 2 completion: Memory system implementation details
- Phase 3 completion: Research capabilities and tool integration
- Session documentation: Model testing, VRAM optimization analysis
- Test results: Comprehensive prompt testing (v1_verbose: 87/100)
- Tool logging implementation guide

## System Prompts
- Added prompts.py with 7 tested variants for A/B testing
- v1_verbose, v2_concise, v3_imperative, v4_minimal, etc.
- Comprehensive testing results for each variant
- Production-ready prompt selection guidance

## Memory System Enhancements
- Multi-tenancy support: Added user_id parameter throughout
- System message filtering: Don't store system messages in history
- Improved conversation turn tracking with user isolation
- Enhanced memory manager for better multi-user support

## AI Controller Improvements
- Better memory integration with user_id support
- Enhanced error handling for memory operations
- Improved token tracking for usage monitoring
- Skip system message storage (part of agent state)

## Portainer Client
- Comprehensive API client (148 lines)
- Stack management and service monitoring
- Container operations with full error handling
- Async support for all operations

## Architecture Documentation
- Updated agent flow diagrams for ADK architecture
- Enhanced core-api README with current setup
- Updated Docker compose stack configuration
- Complete testing and validation documentation

services/core-api/README.md

@@ -44,6 +44,28 @@ pip install -r requirements.txt
 uvicorn src.main:app --reload --host 0.0.0.0 --port 8083
 ```
 
+### Adding New Dependencies
+
+**Important**: Dependencies use major version pinning (`~=`) for automatic patch updates while preventing breaking changes.
+
+1. Add package to `requirements.txt` with major version constraint:
+   ```
+   package-name~=1.2.0  # Allows 1.2.x, blocks 1.3.0
+   ```
+
+2. Restart the container to install:
+   ```bash
+   docker restart core-api
+   ```
+
+The container automatically runs `pip install -r requirements.txt` on every boot, so new dependencies are installed immediately on restart.
+
+**Version Pinning Best Practices**:
+- Use `~=` (compatible release) for most packages: `fastapi~=0.115.0`
+- Use `>=X,<Y` for complex constraints: `langchain-core>=0.3.17,<0.4.0`
+- Allows automatic security patches without breaking changes
+- Documented in PEP 440
+
 ### Docker Build
 
 ```bash