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

shared/strategies/news_driven.py

@@ -10,12 +10,12 @@ class NewsDrivenStrategy(BaseStrategy):
     """Generate signals from aggregated news sentiment for a ticker.
 
     **Buy signal** (LONG):
-        ``avg_score > 0.3`` AND ``avg_confidence > 0.5`` AND
-        ``article_count >= 2``.
+        ``avg_score > 0.15`` AND ``avg_confidence > 0.3`` AND
+        ``article_count >= 1``.
 
     **Sell signal** (SHORT):
-        ``avg_score < -0.3`` AND ``avg_confidence > 0.5`` AND
-        ``article_count >= 2``.
+        ``avg_score < -0.15`` AND ``avg_confidence > 0.3`` AND
+        ``article_count >= 1``.
 
     Signal strength = ``abs(avg_score) * avg_confidence``, clamped to
     [0, 1].
@@ -32,17 +32,17 @@ class NewsDrivenStrategy(BaseStrategy):
         if sentiment is None:
             return None
 
-        # Require at least 2 articles for statistical confidence.
-        if sentiment.article_count < 2:
+        # Require at least 1 article.
+        if sentiment.article_count < 1:
             return None
 
         # Require minimum confidence.
-        if sentiment.avg_confidence <= 0.5:
+        if sentiment.avg_confidence <= 0.3:
             return None
 
-        if sentiment.avg_score > 0.3:
+        if sentiment.avg_score > 0.15:
             direction = SignalDirection.LONG
-        elif sentiment.avg_score < -0.3:
+        elif sentiment.avg_score < -0.15:
             direction = SignalDirection.SHORT
         else:
             # Sentiment is neutral — no opinion.