feat: ensure ui automatically updates regardless of version number

Task #53 completed by ClaudeQueue

ClaudeQueue

server/server.js

@@ -24,6 +24,7 @@ import { serveStatic }  from 'hono/bun';
 import { logger }       from 'hono/logger';
 import { spawnSync }    from 'node:child_process';
 import { createServer } from 'node:http';
+import { readFileSync }  from 'node:fs';
 import { initDb, upsertUser, recordVideoAccess, getUserData } from './db.js';
 
 const PORT        = parseInt(process.env.PORT || '3000', 10);
@@ -333,6 +334,35 @@ app.get('/api/user/data', async (c) => {
   }
 });
 
+// ============================================================================
+// GET /sw.js — serve the service worker with BUILD_TAG injected
+//
+// The raw sw.js file contains the placeholder `__BUILD_TAG__` which is
+// replaced here with the actual BUILD_TAG string so the SW's cache name
+// tracks the deployment automatically — no manual version bump needed.
+// Served with no-store cache headers so browsers always re-fetch it and
+// pick up the substituted value rather than a browser-cached stale copy.
+// ============================================================================
+let _swSource = null;
+app.get('/sw.js', (c) => {
+  if (!_swSource) {
+    try {
+      _swSource = readFileSync('./public/sw.js', 'utf8');
+    } catch {
+      return c.text('Service worker not found', 404);
+    }
+  }
+  // Inject the build tag: replace the placeholder with the real value.
+  const src = _swSource.replace(
+    "typeof __BUILD_TAG__ !== 'undefined' ? __BUILD_TAG__ : 'v1.0.3'",
+    JSON.stringify(BUILD_TAG)
+  );
+  return c.text(src, 200, {
+    'Content-Type': 'application/javascript; charset=utf-8',
+    'Cache-Control': 'no-store, no-cache, must-revalidate',
+  });
+});
+
 // ============================================================================
 // Static files — serve the frontend/public directory
 // Must come AFTER all /api routes so API takes priority