test: e2e + unit tests for supervisor, proxy, and feature flags

- test_supervisor.py: 28 tests covering load_workflows, resolve_schedule,
  is_due, topological_waves, and proxy round-robin / sticky selection
- test_feature_flags.py: 31 tests covering migration 0019, is_flag_enabled,
  feature_gate decorator, admin toggle routes, and full toggle e2e flows
- conftest.py: seed feature flags with production defaults (markets=1,
  others=0) so all routes behave consistently in tests
- Fix is_flag_enabled bug: replace non-existent db.execute_fetchone()
  with fetch_one() helper
- Update 4 test_waitlist / test_businessplan tests that relied on
  WAITLIST_MODE patches — now enable the relevant DB flag instead

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/tests/conftest.py

@@ -54,6 +54,20 @@ async def db():
     conn.row_factory = aiosqlite.Row
     await conn.execute("PRAGMA foreign_keys=ON")
     await conn.executescript(schema_ddl)
+    # Seed feature flags so routes that use feature_gate() pass through by default.
+    # Tests that specifically test gated behaviour set the flag to 0 via _set_flag().
+    await conn.executescript("""
+        INSERT OR IGNORE INTO feature_flags (name, enabled, description)
+            VALUES ('markets', 1, 'Market/SEO content pages');
+        INSERT OR IGNORE INTO feature_flags (name, enabled, description)
+            VALUES ('payments', 0, 'Paddle billing & checkout');
+        INSERT OR IGNORE INTO feature_flags (name, enabled, description)
+            VALUES ('planner_export', 0, 'Business plan PDF export');
+        INSERT OR IGNORE INTO feature_flags (name, enabled, description)
+            VALUES ('supplier_signup', 0, 'Supplier onboarding wizard');
+        INSERT OR IGNORE INTO feature_flags (name, enabled, description)
+            VALUES ('lead_unlock', 0, 'Lead credit purchase & unlock');
+    """)
     await conn.commit()
 
     original_db = core._db