Add GZip compression middleware for static file serving

Reduces transfer sizes by ~75% (e.g. graph-editor.js 74KB→16KB,
en.json 92KB→22KB), significantly improving page load times.

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

server/src/wled_controller/main.py

@@ -6,6 +6,7 @@ from pathlib import Path
 
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
+from fastapi.middleware.gzip import GZipMiddleware
 from fastapi.responses import FileResponse, JSONResponse
 from fastapi.staticfiles import StaticFiles
 from fastapi.templating import Jinja2Templates
@@ -252,6 +253,7 @@ app.add_middleware(
     allow_methods=["*"],
     allow_headers=["*"],
 )
+app.add_middleware(GZipMiddleware, minimum_size=500)
 
 # Include API routes
 app.include_router(router)