Reduce egress costs, add PWA support, fix Polymarket and Railway relay

Egress optimization:
- Add s-maxage + stale-while-revalidate to all API endpoints for Vercel CDN caching
- Add vercel.json with immutable caching for hashed assets
- Add gzip compression to sidecar responses >1KB
- Add gzip to Railway RSS responses (4 paths previously uncompressed)
- Increase polling intervals: markets/crypto 60s→120s, ETF/macro/stablecoins 60s→180s
- Remove hardcoded Railway URL from theater-posture.js (now env-var only)

PWA / Service Worker:
- Add vite-plugin-pwa with autoUpdate strategy
- Cache map tiles (CacheFirst), fonts (StaleWhileRevalidate), static assets
- NetworkOnly for all /api/* routes (real-time data must be fresh)
- Manual SW registration (web only, skip Tauri)
- Add offline fallback page
- Replace manual manifest with plugin-generated manifest

Polymarket fix:
- Route dev proxy through production Vercel (bypasses JA3 blocking)
- Add 4th fallback tier: production URL as absolute fallback

Desktop/Sidecar:
- Dual-backend cache (_upstash-cache.js): Redis cloud + in-memory+file desktop
- Settings window OK/Cancel redesign
- Runtime config and secret injection improvements

api/wingbits/[[...path]].js

@@ -70,7 +70,7 @@ export default async function handler(req) {
       return Response.json(data, {
         headers: {
           ...corsHeaders,
-          'Cache-Control': 'public, max-age=86400', // 24h - aircraft details rarely change
+          'Cache-Control': 'public, max-age=86400, s-maxage=86400, stale-while-revalidate=3600', // 24h - aircraft details rarely change
         },
       });
     } catch (error) {
@@ -194,7 +194,7 @@ export default async function handler(req) {
       return Response.json(data, {
         headers: {
           ...corsHeaders,
-          'Cache-Control': 'public, max-age=30', // 30 seconds - live data
+          'Cache-Control': 'public, max-age=30, s-maxage=30, stale-while-revalidate=15', // 30 seconds - live data
         },
       });
     } catch (error) {
@@ -259,7 +259,7 @@ export default async function handler(req) {
       return Response.json(data, {
         headers: {
           ...corsHeaders,
-          'Cache-Control': 'public, max-age=30',
+          'Cache-Control': 'public, max-age=30, s-maxage=30, stale-while-revalidate=15',
         },
       });
     } catch (error) {