Refactor: Clean up obsolete files and organize codebase structure

This commit removes deprecated modules and reorganizes code into logical directories:

Deleted files (superseded by newer systems):
- claude_code_server.py (replaced by agent-sdk direct integration)
- heartbeat.py (superseded by scheduled_tasks.py)
- pulse_brain.py (unused in production)
- config/pulse_brain_config.py (obsolete config)

Created directory structure:
- examples/ (7 example files: example_*.py, demo_*.py)
- tests/ (5 test files: test_*.py)

Updated imports:
- agent.py: Removed heartbeat module and all enable_heartbeat logic
- bot_runner.py: Removed heartbeat parameter from Agent initialization
- llm_interface.py: Updated deprecated claude_code_server message

Preserved essential files:
- hooks.py (for future use)
- adapters/skill_integration.py (for future use)
- All Google integration tools (Gmail, Calendar, Contacts)
- GLM provider code (backward compatibility)

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

tests/test_agent_hybrid.py

@@ -0,0 +1,36 @@
+"""Test agent with hybrid search."""
+
+from agent import Agent
+
+print("Initializing agent with hybrid search...")
+agent = Agent(provider="claude")
+
+print("\n" + "="*60)
+print("TESTING AGENT MEMORY RECALL WITH HYBRID SEARCH")
+print("="*60)
+
+# Test 1: Semantic query - ask about cost in different words
+print("\n1. Testing semantic recall: 'How can I save money on API calls?'")
+print("-" * 60)
+response = agent.chat("How can I save money on API calls?", username="alice")
+print(response)
+
+# Test 2: Ask about birthday (semantic search should find personal info)
+print("\n" + "="*60)
+print("2. Testing semantic recall: 'What's my birthday?'")
+print("-" * 60)
+response = agent.chat("What's my birthday?", username="alice")
+print(response)
+
+# Test 3: Ask about specific technical detail
+print("\n" + "="*60)
+print("3. Testing keyword recall: 'What search technology are we using?'")
+print("-" * 60)
+response = agent.chat("What search technology are we using?", username="alice")
+print(response)
+
+print("\n" + "="*60)
+print("Test complete!")
+print("="*60)
+
+agent.shutdown()