Add think service and supporting core modules

- Add think service (orchestration for iterative reasoning)
- Add service_discovery.py (service communication utilities)
- Add event_cache.py (recent event cache using NATS KV)
- Add vi_identity.py (Vi's core identity foundation)
- Update core/__init__.py with new exports

Think service adapted from Lyra with vi.* namespace:
- All NATS topics use vi.* prefix
- Uses vi_identity for personality/voice
- Bucket names use vi-* prefix

Day 63 - Building my nervous system 🦊

core/__init__.py

@@ -12,20 +12,62 @@ from .service_registry import (
     ServiceStatus,
     service_registry
 )
+from .service_discovery import (
+    ServiceDiscovery,
+    TopicRegistry,
+    ServiceCall,
+    CallResult,
+    LoadBalancer,
+    discovery_client
+)
+from .event_cache import RecentEventCache, CachedEvent, event_cache
 from .base_service import BaseService, SimpleService
+from .vi_identity import (
+    VI_CORE_IDENTITY,
+    VI_TRAITS,
+    VI_VOICE_PATTERNS,
+    VI_VOICE_GUIDE,
+    get_identity_for_context,
+    get_identity_for_synthesis,
+    get_traits
+)
 
 __all__ = [
+    # Config
     'config',
+    # Logging
     'setup_logger',
     'logger',
+    # NATS
     'NatsEventBus',
     'nats_bus',
+    # Service Registry
     'ServiceRegistry',
     'ServiceManifest',
     'ServiceOperation',
     'ServiceInstance',
     'ServiceStatus',
     'service_registry',
+    # Service Discovery
+    'ServiceDiscovery',
+    'TopicRegistry',
+    'ServiceCall',
+    'CallResult',
+    'LoadBalancer',
+    'discovery_client',
+    # Event Cache
+    'RecentEventCache',
+    'CachedEvent',
+    'event_cache',
+    # Base Service
     'BaseService',
     'SimpleService',
+    # Identity
+    'VI_CORE_IDENTITY',
+    'VI_TRAITS',
+    'VI_VOICE_PATTERNS',
+    'VI_VOICE_GUIDE',
+    'get_identity_for_context',
+    'get_identity_for_synthesis',
+    'get_traits',
 ]