T10: Monitoring, Performance, Documentation & Environment Config — 38 tests, ruff clean, docs OK

- Extended health endpoint: DB+Redis+Storage+Worker checks with degraded status
- Prometheus metrics endpoint: admin-only, text/plain format
- Metrics: http_requests_total, db_pool_connections, arq_jobs_total
- Structured JSON logging (structlog): timestamp, level, method, path, status, duration_ms, tenant_id
- Performance: page_size max 100 enforced (422), streaming CSV export (StreamingResponse)
- Scripts: seed_perf_data.py, check_indexes.py
- Docs: admin-guide.md (Deploy, Backup, Restore, Env-Vars, Troubleshooting), api-overview.md
- README updated: prod setup, API section, env profiles, admin-guide link
- .env.example: added SECRET_KEY, STORAGE_PATH, SMTP_* vars
- 38 new tests, full regression 564/564 pass (0 failures)
- Ruff: all checks passed

scripts/check_indexes.py

@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+"""Check database indexes — verify all required indexes exist for performance.
+
+Usage:
+    python scripts/check_indexes.py
+
+Checks that critical indexes for contacts, companies, and tenant scoping
+are present in the database.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import os
+import sys
+
+# Add project root to path
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from sqlalchemy import text
+from sqlalchemy.ext.asyncio import create_async_engine
+
+from app.config import get_settings
+
+
+# Required indexes for performance (table, index_name)
+REQUIRED_INDEXES = [
+    ("contacts", "ix_contacts_tenant_deleted"),
+    ("contacts", "ix_contacts_tenant_name"),
+    ("contacts", "ix_contacts_email"),
+    ("companies", "ix_companies_tenant_deleted"),
+    ("companies", "ix_companies_tenant_name"),
+    ("companies", "ix_companies_industry"),
+    ("company_contacts", "ix_cc_company"),
+    ("company_contacts", "ix_cc_contact"),
+]
+
+
+async def check_indexes() -> int:
+    """Check that all required indexes exist in the database.
+
+    Returns 0 if all indexes present, 1 if any missing.
+    """
+    settings = get_settings()
+    engine = create_async_engine(settings.database_url)
+
+    missing: list[tuple[str, str]] = []
+    present: list[tuple[str, str]] = []
+
+    async with engine.connect() as conn:
+        for table_name, index_name in REQUIRED_INDEXES:
+            result = await conn.execute(
+                text(
+                    "SELECT 1 FROM pg_indexes "
+                    "WHERE schemaname = 'public' "
+                    "AND tablename = :table "
+                    "AND indexname = :index"
+                ),
+                {"table": table_name, "index": index_name},
+            )
+            if result.scalar():
+                present.append((table_name, index_name))
+                print(f"  ✓ {table_name}.{index_name}")
+            else:
+                missing.append((table_name, index_name))
+                print(f"  ✗ MISSING: {table_name}.{index_name}")
+
+    await engine.dispose()
+
+    print(f"\nSummary: {len(present)} present, {len(missing)} missing")
+    if missing:
+        print("\nMissing indexes:")
+        for table, idx in missing:
+            print(f"  - {table}.{idx}")
+        return 1
+
+    print("\nAll required indexes present!")
+    return 0
+
+
+def main():
+    """Run index check."""
+    print("Checking database indexes...")
+    exit_code = asyncio.run(check_indexes())
+    sys.exit(exit_code)
+
+
+if __name__ == "__main__":
+    main()