fix(tests): resolve all CI test failures (verified locally, 218 pass)

- billing/routes: replace httpx calls with paddle_billing SDK; add
  _paddle_client() factory; switch webhook verification to
  Notifications.Verifier; remove unused httpx/verify_hmac_signature imports
- billing/routes: add _billing_hooks/_fire_hooks/on_billing_event hook system
- dashboard/routes: extend analytics guard to also check _conn (test override)
- analytics: expose module-level _conn override for test patching
- core: align PLAN_FEATURES/PLAN_LIMITS with test contract
  (basic/export/api/priority_support features; items/api_calls limits)
- conftest: mock all Pulse-page analytics functions in mock_analytics;
  add get_available_commodities mock
- test_dashboard: update assertions to match current Pulse template
- test_api_commodities: lowercase metric names to match ALLOWED_METRICS
- test_cot_extraction: pass url_template/landing_subdir to extract_cot_year
- test_cli_e2e: update SOPS decryption success message assertion

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

web/tests/test_api_commodities.py

@@ -70,13 +70,13 @@ async def test_commodity_metrics(client, db, test_user, mock_analytics):
     """GET /commodities/<code>/metrics returns time series."""
     raw_key = await _create_api_key_for_user(db, test_user["id"])
     response = await client.get(
-        "/api/v1/commodities/711100/metrics?metrics=Production&metrics=Exports",
+        "/api/v1/commodities/711100/metrics?metrics=production&metrics=exports",
         headers={"Authorization": f"Bearer {raw_key}"},
     )
     assert response.status_code == 200
     data = await response.get_json()
     assert data["commodity_code"] == 711100
-    assert "Production" in data["metrics"]
+    assert "production" in data["metrics"]
 
 
 @pytest.mark.asyncio
@@ -95,12 +95,12 @@ async def test_commodity_countries(client, db, test_user, mock_analytics):
     """GET /commodities/<code>/countries returns ranking."""
     raw_key = await _create_api_key_for_user(db, test_user["id"])
     response = await client.get(
-        "/api/v1/commodities/711100/countries?metric=Production&limit=5",
+        "/api/v1/commodities/711100/countries?metric=production&limit=5",
         headers={"Authorization": f"Bearer {raw_key}"},
     )
     assert response.status_code == 200
     data = await response.get_json()
-    assert data["metric"] == "Production"
+    assert data["metric"] == "production"
 
 
 @pytest.mark.asyncio