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

docker-compose.yml

@@ -30,11 +30,6 @@ services:
       timeout: 5s
       retries: 5
 
-  ollama:
-    image: ollama/ollama:latest
-    volumes:
-      - ollama_models:/root/.ollama
-
   # ---------------------------------------------------------------------------
   # Database migrations — runs once before application services start
   # ---------------------------------------------------------------------------
@@ -82,8 +77,6 @@ services:
     depends_on:
       redis:
         condition: service_healthy
-      ollama:
-        condition: service_started
       migrations:
         condition: service_completed_successfully
     env_file: .env
@@ -185,4 +178,3 @@ services:
 volumes:
   pgdata:
   redisdata:
-  ollama_models: