fix(client): make build assets deployment relative

src/client/index.html

@@ -5,9 +5,9 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover" />
     <title>PI WEB</title>
     <meta name="theme-color" content="#0d1117" />
-    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
-    <link rel="apple-touch-icon" href="/apple-touch-icon.png" />
-    <link rel="manifest" href="/manifest.webmanifest" />
+    <link rel="icon" type="image/svg+xml" href="%BASE_URL%favicon.svg" />
+    <link rel="apple-touch-icon" href="%BASE_URL%apple-touch-icon.png" />
+    <link rel="manifest" href="%BASE_URL%manifest.webmanifest" />
     <style>
       :root {
         color-scheme: dark;

src/client/public/manifest.webmanifest

@@ -2,20 +2,20 @@
   "name": "PI WEB",
   "short_name": "PI WEB",
   "description": "Remote web UI and browser control plane for persistent Pi Coding Agent sessions.",
-  "start_url": "/",
-  "scope": "/",
+  "start_url": "./",
+  "scope": "./",
   "display": "standalone",
   "background_color": "#0d1117",
   "theme_color": "#0d1117",
   "icons": [
     {
-      "src": "/pwa-icon-192.png",
+      "src": "./pwa-icon-192.png",
       "sizes": "192x192",
       "type": "image/png",
       "purpose": "any maskable"
     },
     {
-      "src": "/pwa-icon-512.png",
+      "src": "./pwa-icon-512.png",
       "sizes": "512x512",
       "type": "image/png",
       "purpose": "any maskable"