Implement GlyphOS Event System

Add lightweight, in-process event bus with Cognitive Kernel integration:

New Components:
- glyphos/events.py: EventBus class + functional API
  * EventBus: publish/subscribe pattern with history
  * Event type definitions (EventType literal)
  * Singleton: get_event_bus(), emit(), on()
  * History filtering and limits
  * Graceful handler error handling

- tests/test_events.py: Comprehensive test suite (16 tests, 100% pass)
  * EventBus subscription/publishing/history
  * Global singleton behavior
  * Functional API (on, emit, get_event_bus)
  * Kernel integration tests
  * Cognition event emission tests

Modified:
- glyphos/cognitive_kernel.py: Event emissions at key points
  * kernel.warmup.completed: After warmup() completes
  * cognition.started: At start of execute_gx()
  * cognition.completed: After execute_gx() completes
  * glyph.resonance.updated: When glyph resonance present

- glyphos/__init__.py: Export events module

Test Results:
- Registry tests:          12/12 ✅
- Bridge tests:            10/10 ✅
- Kernel tests:             8/8  ✅
- Event system tests:      16/16 ✅ (NEW)
- Integration tests:        6/6  ✅
- Total:                   52/52 ✅

No breaking changes - all 36 existing tests still pass.

glyphos/__init__.py

@@ -1,7 +1,9 @@
-"""GlyphOS Cognitive Kernel
+"""GlyphOS - Cognitive Kernel and Event System
 
 A system service layer on top of LAIN cognition engine and Supercharged Glyph Registry.
-Provides a clean, structured API for running cognition on GX files and managing glyph context.
+Provides:
+- Cognitive Kernel: Clean API for running cognition on GX files
+- Event System: Lightweight in-process event bus for symbolic events
 """
 
 from .cognitive_kernel import (
@@ -11,9 +13,24 @@ from .cognitive_kernel import (
     kernel_status,
 )
 
+from .events import (
+    EventBus,
+    Event,
+    EventType,
+    get_event_bus,
+    emit,
+    on,
+)
+
 __all__ = [
     "CognitiveKernel",
     "get_kernel",
     "run_gx",
     "kernel_status",
+    "EventBus",
+    "Event",
+    "EventType",
+    "get_event_bus",
+    "emit",
+    "on",
 ]