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>

ledger/migrations/STATUS.md

@@ -0,0 +1,71 @@
+# Status: Ledger Migrations
+
+## Current Phase
+
+**COMPLETE**
+
+## Tasks
+
+| Status | Task | Updated |
+|--------|------|---------|
+| ✅ | Migration 001: Multi-tenant tables | 2026-01-24 |
+| ✅ | Migration 002: Marketplace tables | 2026-01-24 |
+| ✅ | Indices for query optimization | 2026-01-24 |
+| ✅ | FTS5 search index | 2026-01-24 |
+
+## Migrations Applied
+
+| # | File | Tables | Status |
+|---|------|--------|--------|
+| 001 | `001_multi_tenant.sql` | 7 tables | ✅ Applied |
+| 002 | `002_marketplace.sql` | 6 tables | ✅ Applied |
+
+## Tables Created
+
+### Phase 10 (Multi-Tenant)
+- `tenants`
+- `projects`
+- `tenant_quotas`
+- `tenant_usage`
+- `api_keys`
+- `user_roles`
+- `audit_log_tenant`
+
+### Phase 11 (Marketplace)
+- `agent_templates`
+- `template_versions`
+- `template_installations`
+- `template_ratings`
+- `template_downloads`
+- `templates_fts` (FTS5 virtual table)
+
+## Dependencies
+
+| Dependency | Status | Purpose |
+|------------|--------|---------|
+| SQLite 3.x | ✅ Available | Database engine |
+| FTS5 | ✅ Available | Full-text search |
+
+## Issues / Blockers
+
+*No current issues or blockers.*
+
+## Activity Log
+
+### 2026-01-24 UTC
+- **Phase**: COMPLETE
+- **Action**: Documentation added
+- **Details**: Created README.md and STATUS.md
+
+### 2026-01-24 12:27 UTC
+- **Phase**: COMPLETE
+- **Action**: Marketplace migration added
+- **Details**: Created 002_marketplace.sql with template tables
+
+### 2026-01-24 12:16 UTC
+- **Phase**: COMPLETE
+- **Action**: Multi-tenant migration added
+- **Details**: Created 001_multi_tenant.sql with tenant tables
+
+---
+*Last updated: 2026-01-24 UTC*