feat: Implement high-impact code optimizations

- Migrate from Flask to Quart (async) for better concurrency
- Add httpx with HTTP/2 connection pooling for Telegram
- Add diskcache for caching health check responses
- Increase ThreadPoolExecutor workers from 4 to 8 (configurable)
- Remove hardcoded paths - use environment variables
- Add circuit breaker pattern for resilient external calls
- Add proper timeout handling for health checks
- Pin all dependencies in requirements.txt
- Add graceful startup/shutdown handlers
- Pre-warm agent in background thread on startup

requirements.txt

@@ -1,2 +1,19 @@
-flask>=3.0
-requests>=2.31
+# Core dependencies - pinned versions for reproducible builds
+flask==3.0.3
+requests==2.32.3
+
+# Async/Production dependencies
+quart==0.19.4
+uvicorn[standard]==0.30.6
+gunicorn==22.0.0
+
+# Performance optimizations
+httpx==0.27.2       # HTTP/2 connection pooling for Telegram
+diskcache==5.6.3    # Semantic caching
+brotli==1.1.0       # Compression
+
+# Resilience patterns
+tenacity==8.5.0     # Retry logic with exponential backoff
+
+# Type hints support
+typing_extensions==4.12.2