feat: productionize local service — fix signal pipeline, lower thresholds, add company-name ticker extraction

- Point Ollama to local instance via host.docker.internal, use gemma3 model
- Remove Docker Ollama service (using host's Ollama instead)
- Add company-name-to-ticker mapping (Apple→AAPL, Tesla→TSLA, etc.) for RSS articles
- Lower signal thresholds for faster feedback with paper trading:
  - FinBERT confidence: 0.6→0.4, signal strength: 0.3→0.15
  - News strategy: article_count 2→1, confidence 0.5→0.3, score ±0.3→±0.15
- Fix market data BarSet access bug (BarSet.__contains__ returns False incorrectly)
- Fix market data SIP feed error by switching to IEX feed for free Alpaca accounts
- Fix nginx proxy routing for /api/auth/* to api-gateway /auth/*
- Add seed_sample_data script
- Update tests for new thresholds and alpaca mock modules

tests/services/test_market_data.py

@@ -97,6 +97,9 @@ def _install_alpaca_mocks():
     historical_mod = ModuleType("alpaca.data.historical")
     historical_mod.StockHistoricalDataClient = MagicMock
 
+    enums_mod = ModuleType("alpaca.data.enums")
+    enums_mod.DataFeed = MagicMock()
+
     # Build the package hierarchy
     alpaca_mod = sys.modules.get("alpaca") or ModuleType("alpaca")
     data_mod = sys.modules.get("alpaca.data") or ModuleType("alpaca.data")
@@ -106,6 +109,7 @@ def _install_alpaca_mocks():
     sys.modules["alpaca.data.timeframe"] = timeframe_mod
     sys.modules["alpaca.data.requests"] = requests_mod
     sys.modules["alpaca.data.historical"] = historical_mod
+    sys.modules["alpaca.data.enums"] = enums_mod
 
 
 # Install mocks before importing from market_data.main