feat(acars): add message translator and ADS-B datalink integration

Add ACARS label translation, message classification, and field parsers
so decoded messages show human-readable descriptions instead of raw
label codes (H1, DF, _d, 5Z, etc.). Integrate translated ACARS
messages into the ADS-B aircraft detail panel and add a live message
feed to the standalone ACARS mode.

- New utils/acars_translator.py with ~50 label codes, type classifier,
  and parsers for position reports, engine data, weather, and OOOI
- Enrich messages at ingest in routes/acars.py with translation fields
- Backfill translation in /adsb/aircraft/<icao>/messages endpoint
- ADS-B dashboard: DATALINK MESSAGES section in aircraft detail panel
  with auto-refresh, color-coded type badges, and parsed field display
- Standalone ACARS mode: scrollable live message feed (max 30 cards)
- Fix default N. America ACARS frequencies to 131.550/130.025/129.125
- Unit tests covering all translator functions

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

docker-compose.yml

@@ -29,6 +29,7 @@ services:
       # Optional: mount logs directory
       # - ./logs:/app/logs
     environment:
+      - TZ=${TZ:-UTC}
       - INTERCEPT_HOST=0.0.0.0
       - INTERCEPT_PORT=5050
       - INTERCEPT_LOG_LEVEL=INFO
@@ -78,6 +79,7 @@ services:
     volumes:
       - ./data:/app/data
     environment:
+      - TZ=${TZ:-UTC}
       - INTERCEPT_HOST=0.0.0.0
       - INTERCEPT_PORT=5050
       - INTERCEPT_LOG_LEVEL=INFO
@@ -108,6 +110,7 @@ services:
     profiles:
       - history
     environment:
+      - TZ=${TZ:-UTC}
       - POSTGRES_DB=intercept_adsb
       - POSTGRES_USER=intercept
       - POSTGRES_PASSWORD=intercept