perf(web): gzip response compression via flask-compress

The interface ships a ~5,000-line HTML shell and >20k lines of JS
uncompressed; on phone/WiFi that dominates load time. Flask-Compress
gzips/brotlis compressible responses transparently.

- Optional dependency, same graceful pattern as flask-limiter: missing
  package = uncompressed responses, no crash.
- SSE safety verified empirically against the real package (1.24): an
  actual streamed text/event-stream response comes back with no
  Content-Encoding while a large HTML response gzips — the display
  preview / stats / logs streams are unaffected.
- Added flask-compress>=1.14 to web_interface/requirements.txt.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KEZK1P1Q1fu5pcuVrkrCFZ

web_interface/app.py

@@ -59,6 +59,16 @@ except ImportError:
     # flask-limiter not installed, rate limiting disabled
     limiter = None
 
+# Enable gzip/brotli response compression (Flask-Compress skips streaming
+# responses, so the SSE endpoints are unaffected). Optional, like limiter:
+# missing package just means uncompressed responses.
+try:
+    from flask_compress import Compress
+
+    Compress(app)
+except ImportError:
+    pass
+
 # Import cache functions from separate module to avoid circular imports
 
 # Initialize plugin managers - read plugins directory from config

web_interface/requirements.txt

@@ -7,6 +7,7 @@ flask>=3.1.3,<4.0.0
 werkzeug>=3.1.6,<4.0.0
 flask-wtf>=1.2.0  # CSRF protection (optional for local-only, but recommended)
 flask-limiter>=3.5.0  # Rate limiting (prevent accidental abuse)
+flask-compress>=1.14  # gzip/brotli response compression (big win for the large JS/HTML over WiFi)
 
 # WebSocket support for plugins
 # Note: Web interface uses Server-Sent Events (SSE) for real-time updates, not WebSockets