feat(spaces): implement Phase 2 Event System

Week 4 - Event Infrastructure:
- Create SpaceEventType enum with 18 event types covering space lifecycle,
  document operations, variables, references, rendering, sync, and cache
- Create SpaceEvent dataclass with serialization/deserialization
- Create EventBus with sync/async handler support, priority ordering,
  global handlers, and optional event history
- Add event factory functions for common events

Week 5 - Event Integration:
- Wire EventBus into SpaceService as optional dependency
- Emit events for all space operations:
  - SPACE_CREATED, SPACE_UPDATED, SPACE_DELETED, SPACE_ACTIVATED, SPACE_ARCHIVED
  - DOCUMENT_ADDED, DOCUMENT_REMOVED, DOCUMENT_MOVED, DOCUMENT_CONTENT_CHANGED
  - VARIABLE_SET, VARIABLE_DELETED
- Create integration tests for event propagation patterns

Test coverage: 187 tests total
- 43 unit tests for event system
- 20 integration tests for event propagation
- 124 existing tests continue to pass

Capabilities delivered:
- CAP-010: SpaceEvent base with type, payload, timestamp
- CAP-011: EventBus with in-process publish/subscribe
- CAP-012: Event handlers registry with priority support
- CAP-013: Change detection via content hash comparison

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

markitect/spaces/events/__init__.py

@@ -3,14 +3,55 @@ Event system for Information Spaces.
 
 This package provides event-driven architecture for space operations:
 - SpaceEvent: Event dataclass with type, payload, timestamp
+- SpaceEventType: Enum of all event types
 - EventBus: In-process publish/subscribe for space events
-- Event handlers and registration
+- Event factory functions for common events
 
 Events emitted:
-- SPACE_CREATED, SPACE_UPDATED, SPACE_DELETED
-- DOCUMENT_ADDED, DOCUMENT_UPDATED, DOCUMENT_REMOVED
-- RENDER_COMPLETED, SYNC_COMPLETED
+- Space lifecycle: SPACE_CREATED, SPACE_UPDATED, SPACE_DELETED, SPACE_ACTIVATED, SPACE_ARCHIVED
+- Document: DOCUMENT_ADDED, DOCUMENT_UPDATED, DOCUMENT_REMOVED, DOCUMENT_MOVED, DOCUMENT_CONTENT_CHANGED
+- Variable: VARIABLE_SET, VARIABLE_DELETED
+- Reference: REFERENCE_ADDED, REFERENCE_CLEARED
+- Rendering: RENDER_STARTED, RENDER_COMPLETED, RENDER_FAILED
+- Sync: SYNC_STARTED, SYNC_COMPLETED, SYNC_CONFLICT
+- Cache: CACHE_INVALIDATED
 """
 
-# Events will be implemented in Phase 2
-__all__ = []
+from .models import (
+    SpaceEvent,
+    SpaceEventType,
+    space_created_event,
+    space_updated_event,
+    space_deleted_event,
+    document_added_event,
+    document_updated_event,
+    document_removed_event,
+    document_content_changed_event,
+    cache_invalidated_event,
+)
+from .bus import (
+    EventBus,
+    HandlerRegistration,
+    get_event_bus,
+    reset_event_bus,
+)
+
+__all__ = [
+    # Event models
+    "SpaceEvent",
+    "SpaceEventType",
+    # Event factories
+    "space_created_event",
+    "space_updated_event",
+    "space_deleted_event",
+    "document_added_event",
+    "document_updated_event",
+    "document_removed_event",
+    "document_content_changed_event",
+    "cache_invalidated_event",
+    # Event bus
+    "EventBus",
+    "HandlerRegistration",
+    "get_event_bus",
+    "reset_event_bus",
+]