Implement Tefter per SPEC.md: NV-style notes with server, sync, PWA, desktop

- frontend/: Svelte 4 + TS + Vite app — omnibar (search-and-create), ranked
  diacritic-insensitive filtering, CodeMirror 6 markdown editor with 400ms
  autosave, marked+DOMPurify preview with [[wiki-links]], tag filter, undo
  toast, light/dark, narrow-screen stacked layout, IndexedDB store, pull-then-
  push sync engine with conflict handling, versioned cache-first service
  worker + manifest (installable PWA)
- server/: tefterd — Go stdlib HTTP + modernc.org/sqlite, /api/v1 sync API
  (changes/batch/health/import), SHA-256 hashed bearer token, LWW-with-
  conflict-copies push rules, subcommands: init, token rotate, import
  simplenote, compact, backup (VACUUM INTO); embeds the frontend bundle
- desktop/: Wails v2 shell — single instance, hide-to-tray (fyne systray),
  global Ctrl+Shift+Space hotkey, quit-on-close flag
- Simplenote import (CLI + web upload), idempotent via source_id dedupe;
  verified against a real 242-note export
- Makefile (frontend/server/server-all/desktop/test), GitHub release workflow,
  README with systemd/Caddy/backup docs

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/vite.config.ts

@@ -0,0 +1,67 @@
+import { defineConfig, type Plugin } from 'vite';
+import { svelte } from '@sveltejs/vite-plugin-svelte';
+import { createHash } from 'node:crypto';
+
+const version = process.env.TEFTER_VERSION || 'dev';
+
+// Emits sw.js at build time with the precache list of all emitted assets,
+// versioned by a hash of the file names (which themselves carry content hashes).
+function serviceWorker(): Plugin {
+  return {
+    name: 'tefter-sw',
+    apply: 'build',
+    generateBundle(_opts, bundle) {
+      const assets = Object.keys(bundle)
+        .filter((f) => !f.endsWith('.map'))
+        .map((f) => '/' + f);
+      assets.push('/', '/manifest.webmanifest', '/icon-192.png', '/icon-512.png');
+      const hash = createHash('sha256').update(assets.join(',') + version).digest('hex').slice(0, 12);
+      const sw = `// generated by vite.config.ts — do not edit
+const CACHE = 'tefter-${'${'}HASH}';
+const ASSETS = ${'${'}ASSETS};
+
+self.addEventListener('install', (e) => {
+  e.waitUntil(caches.open(CACHE).then((c) => c.addAll(ASSETS)).then(() => self.skipWaiting()));
+});
+
+self.addEventListener('activate', (e) => {
+  e.waitUntil(
+    caches.keys()
+      .then((keys) => Promise.all(keys.filter((k) => k !== CACHE).map((k) => caches.delete(k))))
+      .then(() => self.clients.claim())
+  );
+});
+
+self.addEventListener('fetch', (e) => {
+  const url = new URL(e.request.url);
+  if (e.request.method !== 'GET' || url.origin !== location.origin) return;
+  if (url.pathname.startsWith('/api/')) return; // network-only; sync engine handles offline
+  e.respondWith(
+    caches.match(url.pathname === '/' || url.pathname === '/index.html' ? '/' : e.request).then(
+      (hit) => hit || fetch(e.request)
+    )
+  );
+});
+`
+        .replace('${HASH}', hash)
+        .replace('${ASSETS}', JSON.stringify(assets));
+      this.emitFile({ type: 'asset', fileName: 'sw.js', source: sw });
+    },
+  };
+}
+
+export default defineConfig({
+  plugins: [svelte(), serviceWorker()],
+  define: {
+    __TEFTER_VERSION__: JSON.stringify(version),
+  },
+  build: {
+    target: 'es2020',
+    sourcemap: false,
+  },
+  server: {
+    proxy: {
+      '/api': 'http://127.0.0.1:8420',
+    },
+  },
+});