Replace CORS proxy with complete server-side cache

- Replace cors/ directory and cors.mjs utility with comprehensive
    HTTP caching proxy in proxy/ directory
- Implement RFC-compliant caching with cache-control headers,
    conditional requests, and in-flight deduplication
- Centralized error handling with "safe" fetch utilities
- Add unified proxy handlers for weather.gov, SPC, radar, and mesonet APIs
- Include cache management endpoint and extensive diagnostic logging
- Migrate client-side URL rewriting from cors.mjs to url-rewrite.mjs

proxy/handlers.mjs

@@ -0,0 +1,44 @@
+// Consolidated proxy handlers for all external API requests with caching
+
+import cache from './cache.mjs';
+import OVERRIDES from '../src/overrides.mjs';
+
+// Weather.gov API proxy (catch-all for any Weather.gov API endpoint)
+export const weatherProxy = async (req, res) => {
+	await cache.handleRequest(req, res, 'https://api.weather.gov', {
+		serviceName: 'Weather.gov',
+		skipParams: ['u'],
+	});
+};
+
+// Radar proxy for weather radar images
+export const radarProxy = async (req, res) => {
+	await cache.handleRequest(req, res, 'https://radar.weather.gov', {
+		serviceName: 'Radar',
+		skipParams: ['u'],
+		encoding: 'binary', // Radar images are binary data
+	});
+};
+
+// SPC (Storm Prediction Center) outlook proxy
+export const outlookProxy = async (req, res) => {
+	await cache.handleRequest(req, res, 'https://www.spc.noaa.gov', {
+		serviceName: 'SPC Outlook',
+		skipParams: ['u'],
+	});
+};
+
+// Iowa State Mesonet proxy with configurable host
+export const mesonetProxy = async (req, res) => {
+	// Determine if this is a binary file (images)
+	const isBinary = req.path.match(/\.(png|jpg|jpeg|gif|webp|ico)$/i);
+
+	// Use override radar host if provided, otherwise default to mesonet
+	const radarHost = OVERRIDES.RADAR_HOST || 'mesonet.agron.iastate.edu';
+
+	await cache.handleRequest(req, res, `https://${radarHost}`, {
+		serviceName: `Iowa State Mesonet (${radarHost})`,
+		skipParams: [], // No parameters to skip for Mesonet
+		encoding: isBinary ? 'binary' : 'utf8', // Use binary encoding for images
+	});
+};