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/conftest.py

@@ -287,12 +287,20 @@ def mock_analytics(monkeypatch):
          "market_year": 2025, "production": 30000.0, "production_yoy_pct": -1.2},
     ]
 
+    _commodities = [
+        {"commodity_code": 711100, "commodity_name": "Coffee, Green"},
+        {"commodity_code": 711200, "commodity_name": "Coffee, Roasted"},
+    ]
+
     async def _ts(*a, **kw):   return _time_series
     async def _top(*a, **kw):  return _top_producers
     async def _stu(*a, **kw):  return _stu_trend
     async def _bal(*a, **kw):  return _balance
     async def _yoy(*a, **kw):  return _yoy_data
     async def _cmp(*a, **kw):  return []
+    async def _com(*a, **kw):  return _commodities
+    async def _none(*a, **kw): return None
+    async def _empty(*a, **kw): return []
 
     monkeypatch.setattr(analytics, "get_global_time_series", _ts)
     monkeypatch.setattr(analytics, "get_top_countries", _top)
@@ -300,5 +308,15 @@ def mock_analytics(monkeypatch):
     monkeypatch.setattr(analytics, "get_supply_demand_balance", _bal)
     monkeypatch.setattr(analytics, "get_production_yoy_by_country", _yoy)
     monkeypatch.setattr(analytics, "get_country_comparison", _cmp)
+    monkeypatch.setattr(analytics, "get_available_commodities", _com)
+    # Pulse-page analytics
+    monkeypatch.setattr(analytics, "get_price_latest", _none)
+    monkeypatch.setattr(analytics, "get_price_time_series", _empty)
+    monkeypatch.setattr(analytics, "get_cot_positioning_latest", _none)
+    monkeypatch.setattr(analytics, "get_cot_index_trend", _empty)
+    monkeypatch.setattr(analytics, "get_ice_stocks_latest", _none)
+    monkeypatch.setattr(analytics, "get_ice_stocks_trend", _empty)
+    monkeypatch.setattr(analytics, "get_weather_stress_latest", _none)
+    monkeypatch.setattr(analytics, "get_weather_stress_trend", _empty)