Add Phase 10-12 implementation: multi-tenant, marketplace, observability

Major additions:
- marketplace/: Agent template registry with FTS5 search, ratings, versioning
- observability/: Prometheus metrics, distributed tracing, structured logging
- ledger/migrations/: Database migration scripts for multi-tenant support
- tests/governance/: 15 new test files for phases 6-12 (295 total tests)
- bin/validate-phases: Full 12-phase validation script

New features:
- Multi-tenant support with tenant isolation and quota enforcement
- Agent marketplace with semantic versioning and search
- Observability with metrics, tracing, and log correlation
- Tier-1 agent bootstrap scripts

Updated components:
- ledger/api.py: Extended API for tenants, marketplace, observability
- ledger/schema.sql: Added tenant, project, marketplace tables
- testing/framework.ts: Enhanced test framework
- checkpoint/checkpoint.py: Improved checkpoint management

Archived:
- External integrations (Slack/GitHub/PagerDuty) moved to .archive/
- Old checkpoint files cleaned up

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

integrations/__init__.py

@@ -1,9 +1,15 @@
 """
-External Integrations for Agent Governance System
+Integration Framework for Agent Governance System
 
-Available integrations:
-- GitHub: PR creation, commit status, issue tracking
-- Slack: Notifications, alerts, approval workflows
+Provides base infrastructure for external service integrations.
+Specific integrations (GitHub, Slack, PagerDuty) have been deprecated
+and archived to .archive/integrations/.
+
+Available components:
+- BaseIntegration: Abstract base class for integrations
+- IntegrationManager: Registry and event broadcast
+- SecretsManager: Vault/environment credential access
+- RedisConfig: DragonflyDB connection utilities
 """
 
 from .common.base import (
@@ -12,27 +18,31 @@ from .common.base import (
     BaseIntegration,
     IntegrationManager
 )
-from .github.github import GitHubIntegration
-from .slack.slack import SlackIntegration
+from .common.secrets import SecretsManager, get_secrets, get_secret, require_secret
+from .common.redis_config import RedisConfig, get_redis_client, test_redis_connection
 
 __all__ = [
+    # Base classes
     'IntegrationConfig',
     'IntegrationEvent',
     'BaseIntegration',
     'IntegrationManager',
-    'GitHubIntegration',
-    'SlackIntegration'
+    # Secrets
+    'SecretsManager',
+    'get_secrets',
+    'get_secret',
+    'require_secret',
+    # Redis
+    'RedisConfig',
+    'get_redis_client',
+    'test_redis_connection',
 ]
 
 
 def create_manager() -> IntegrationManager:
-    """Create an integration manager with all available integrations"""
-    manager = IntegrationManager()
+    """Create an empty integration manager.
 
-    # Register GitHub (will be disabled if no token)
-    manager.register(GitHubIntegration())
-
-    # Register Slack (will be disabled if no credentials)
-    manager.register(SlackIntegration())
-
-    return manager
+    External integrations (GitHub, Slack, PagerDuty) have been deprecated.
+    See .archive/integrations/ to restore if needed.
+    """
+    return IntegrationManager()