feat(zerotier): add ZeroTier network governance module

Add comprehensive ZeroTier integration for managing network access:

- Portal networks: manager-created ZeroTier network bindings
- Device registration: user-owned ZeroTier node endpoints
- Approval workflows: request/approve/revoke network access
- Activation sessions: time-limited network authorization
- Kill switch: emergency access revocation
- Reconciliation job: sync portal state with ZeroTier controller

Includes ZeroTier client SDK supporting both Central and self-hosted
controller APIs, with full CRUD operations for networks and members.

scripts/init_db.py

@@ -23,8 +23,12 @@ with app.app_context():
     for i in range(5, 0, -1):
         print(f"{i}...")
         time.sleep(1)
-    db.session.execute(text("DROP SCHEMA public CASCADE"))
-    db.session.execute(text("CREATE SCHEMA public"))
+
+    if db_url.startswith("sqlite"):
+        db.drop_all()
+    else:
+        db.session.execute(text("DROP SCHEMA public CASCADE"))
+        db.session.execute(text("CREATE SCHEMA public"))
     db.session.commit()
 
     # Create all tables