feat(ext/setup): zxcvbn strength meter + score>=3 gate (audit H3)

Replaces the ad-hoc char-class passphraseStrength() with a 5-segment
bar backed by a SW round-trip to rate_passphrase (zxcvbn). Input
handler debounces 150ms so we don't hammer the worker per keystroke.

The create-vault button is disabled unless the last score is ≥ 3
(zxcvbn's "safely unguessable" threshold), and the handler re-rates
synchronously on click as defence-in-depth. Label flips between "Too
weak" (red) and "Strong enough" (green).

Also:
- rewrites the vault-creation path to use the typed-item unlock +
  manifest_encrypt APIs (derive_master_key/encrypt_manifest are gone);
  the new initial manifest is { schema_version: 2, items: {} }.
- wasm.d.ts is now a pure `declare module 'relicario-wasm'` block;
  tsconfig's stale `paths` alias is removed.
- @ts-nocheck removed from setup.ts.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

extension/setup.html

@@ -49,23 +49,38 @@
     }
 
     .strength-bar {
+      display: flex;
+      gap: 3px;
+      margin-top: 6px;
+    }
+
+    .strength-bar .seg {
+      flex: 1;
       height: 4px;
       background: #21262d;
       border-radius: 2px;
-      margin-top: 6px;
-      overflow: hidden;
+      transition: background 0.2s;
     }
 
-    .strength-bar-fill {
-      height: 100%;
-      border-radius: 2px;
-      transition: width 0.2s, background 0.2s;
-    }
+    /* zxcvbn score-driven colors. Higher-scored bars light up earlier bars too. */
+    .strength-bar.s0 .seg.i0 { background: #f85149; }
+    .strength-bar.s1 .seg.i0,
+    .strength-bar.s1 .seg.i1 { background: #db6d28; }
+    .strength-bar.s2 .seg.i0,
+    .strength-bar.s2 .seg.i1,
+    .strength-bar.s2 .seg.i2 { background: #d29922; }
+    .strength-bar.s3 .seg.i0,
+    .strength-bar.s3 .seg.i1,
+    .strength-bar.s3 .seg.i2,
+    .strength-bar.s3 .seg.i3 { background: #3fb950; }
+    .strength-bar.s4 .seg { background: #3fb950; }
 
-    .strength-bar-fill.weak { background: #f85149; width: 25%; }
-    .strength-bar-fill.fair { background: #d29922; width: 50%; }
-    .strength-bar-fill.good { background: #3fb950; width: 75%; }
-    .strength-bar-fill.strong { background: #58a6ff; width: 100%; }
+    .strength-label {
+      font-size: 11px;
+      margin-top: 3px;
+    }
+    .strength-label.weak   { color: #f85149; }
+    .strength-label.strong { color: #3fb950; }
 
     .success-box {
       background: #0d1b0e;

extension/src/setup/setup.ts

@@ -1,4 +1,3 @@
-// @ts-nocheck — transitional: downstream files updated in Slice 6 (item-* rewrites) / Slice 4 (vitest setup) / Slice 5 (content + setup rewires)
 /// Vault initialization wizard — 4-step flow for creating new relicario vaults.
 ///
 /// Step 1: Choose host type (Gitea / GitHub)
@@ -7,7 +6,6 @@
 /// Step 4: Finish (download reference image, push config to extension or copy JSON)
 
 import { createGitHost, uint8ArrayToBase64 } from '../service-worker/git-host';
-import type { GitHost } from '../service-worker/git-host';
 import type { VaultConfig } from '../shared/types';
 
 // --- WASM module (loaded dynamically) ---
@@ -38,6 +36,8 @@ interface WizardState {
   carrierImageBytes: Uint8Array | null;
   passphrase: string;
   passphraseConfirm: string;
+  // zxcvbn meter state — -1 means "not yet scored" (empty passphrase).
+  passphraseScore: number;
   referenceImageBytes: Uint8Array | null;
   creating: boolean;
   error: string | null;
@@ -55,6 +55,7 @@ const state: WizardState = {
   carrierImageBytes: null,
   passphrase: '',
   passphraseConfirm: '',
+  passphraseScore: -1,
   referenceImageBytes: null,
   creating: false,
   error: null,
@@ -72,17 +73,57 @@ function escapeHtml(s: string): string {
     .replace(/"/g, '"');
 }
 
-function passphraseStrength(pw: string): 'weak' | 'fair' | 'good' | 'strong' {
-  let score = 0;
-  if (pw.length >= 8) score++;
-  if (pw.length >= 14) score++;
-  if (/[a-z]/.test(pw) && /[A-Z]/.test(pw)) score++;
-  if (/[0-9]/.test(pw)) score++;
-  if (/[^a-zA-Z0-9]/.test(pw)) score++;
-  if (score <= 1) return 'weak';
-  if (score <= 2) return 'fair';
-  if (score <= 3) return 'good';
-  return 'strong';
+/// Call the SW to score a passphrase with zxcvbn. Returns a score in [0, 4]
+/// per the zxcvbn convention, or -1 if the message round-trip failed.
+function ratePassphrase(passphrase: string): Promise<number> {
+  return new Promise((resolve) => {
+    try {
+      chrome.runtime.sendMessage(
+        { type: 'rate_passphrase', passphrase },
+        (response: { ok: boolean; data?: { score: number; guesses_log10: number }; error?: string }) => {
+          if (chrome.runtime.lastError || !response?.ok) { resolve(-1); return; }
+          resolve(response.data?.score ?? -1);
+        },
+      );
+    } catch {
+      resolve(-1);
+    }
+  });
+}
+
+/// 150ms debounce around the rate_passphrase call so we don't hammer the SW
+/// on every keystroke. The last invocation wins.
+let rateDebounceTimer: ReturnType<typeof setTimeout> | null = null;
+function scheduleRate(passphrase: string, onScore: (score: number) => void): void {
+  if (rateDebounceTimer !== null) clearTimeout(rateDebounceTimer);
+  rateDebounceTimer = setTimeout(async () => {
+    rateDebounceTimer = null;
+    if (!passphrase) { onScore(-1); return; }
+    onScore(await ratePassphrase(passphrase));
+  }, 150);
+}
+
+/// Update just the meter DOM without a full re-render (so the input keeps
+/// focus and the user's cursor position is preserved).
+function updateStrengthUi(): void {
+  const bar = document.getElementById('strength-bar');
+  const label = document.getElementById('strength-label');
+  const create = document.getElementById('create-btn') as HTMLButtonElement | null;
+  const score = state.passphraseScore;
+  if (bar) bar.className = `strength-bar${score >= 0 ? ` s${score}` : ''}`;
+  if (label) {
+    if (score < 0) {
+      label.className = 'strength-label';
+      label.innerHTML = '&nbsp;';
+    } else if (score >= 3) {
+      label.className = 'strength-label strong';
+      label.textContent = 'Strong enough';
+    } else {
+      label.className = 'strength-label weak';
+      label.textContent = 'Too weak';
+    }
+  }
+  if (create) create.disabled = state.creating || score < 3;
 }
 
 // --- Render ---
@@ -267,7 +308,14 @@ function attachStep2(): void {
 // --- Step 3: Create Vault ---
 
 function renderStep3(): string {
-  const strength = state.passphrase ? passphraseStrength(state.passphrase) : null;
+  const score = state.passphraseScore;
+  const hasScore = score >= 0;
+  const meterClass = hasScore ? `s${score}` : '';
+  const labelClass = hasScore ? (score >= 3 ? 'strong' : 'weak') : '';
+  const labelText = !hasScore
+    ? '&nbsp;'
+    : (score >= 3 ? 'Strong enough' : 'Too weak');
+  const gateDisabled = state.creating || score < 3;
 
   return `
     <div class="wizard-step">
@@ -284,21 +332,23 @@ function renderStep3(): string {
       </div>
       <div class="form-group">
         <label class="label" for="passphrase">passphrase</label>
-        <input id="passphrase" type="password" value="${escapeHtml(state.passphrase)}" placeholder="enter a strong passphrase">
-        ${strength ? `
-          <div class="strength-bar">
-            <div class="strength-bar-fill ${strength}"></div>
+        <input id="passphrase" type="password" value="${escapeHtml(state.passphrase)}" placeholder="enter a strong passphrase" autocomplete="new-password">
+        <div class="strength-bar ${meterClass}" id="strength-bar" aria-hidden="true">
+          <div class="seg i0"></div>
+          <div class="seg i1"></div>
+          <div class="seg i2"></div>
+          <div class="seg i3"></div>
+          <div class="seg i4"></div>
         </div>
-          <p class="muted" style="margin-top:2px;">strength: ${strength}</p>
-        ` : ''}
+        <p class="strength-label ${labelClass}" id="strength-label">${labelText}</p>
       </div>
       <div class="form-group">
         <label class="label" for="passphrase-confirm">confirm passphrase</label>
-        <input id="passphrase-confirm" type="password" value="${escapeHtml(state.passphraseConfirm)}" placeholder="re-enter passphrase">
+        <input id="passphrase-confirm" type="password" value="${escapeHtml(state.passphraseConfirm)}" placeholder="re-enter passphrase" autocomplete="new-password">
       </div>
       <div class="form-actions">
         <button class="btn" id="back-btn">back</button>
-        <button class="btn btn-primary" id="create-btn" ${state.creating ? 'disabled' : ''}>
+        <button class="btn btn-primary" id="create-btn" ${gateDisabled ? 'disabled' : ''}>
           ${state.creating ? '<span class="spinner"></span> creating...' : 'create vault'}
         </button>
       </div>
@@ -324,22 +374,14 @@ function attachStep3(): void {
     reader.readAsArrayBuffer(file);
   });
 
-  // Track passphrase changes without full re-render
+  // Track passphrase changes inline (no full re-render) so the input keeps focus.
+  // zxcvbn score is computed via the SW on a 150ms debounce — see scheduleRate.
   document.getElementById('passphrase')?.addEventListener('input', (e) => {
     state.passphrase = (e.target as HTMLInputElement).value;
-    // Update strength bar inline
-    const strength = passphraseStrength(state.passphrase);
-    const bar = document.querySelector('.strength-bar-fill') as HTMLElement | null;
-    const label = document.querySelector('.strength-bar + .muted') as HTMLElement | null;
-    if (bar) {
-      bar.className = `strength-bar-fill ${strength}`;
-    }
-    if (label) {
-      label.textContent = `strength: ${strength}`;
-    }
-    if (!bar && state.passphrase) {
-      render();
-    }
+    scheduleRate(state.passphrase, (score) => {
+      state.passphraseScore = score;
+      updateStrengthUi();
+    });
   });
 
   document.getElementById('passphrase-confirm')?.addEventListener('input', (e) => {
@@ -367,6 +409,15 @@ function attachStep3(): void {
       render();
       return;
     }
+    // Re-rate synchronously in case the button was clicked before the
+    // debounced rater fired. Defence in depth — the button is already
+    // disabled in the UI when score < 3 (audit H3).
+    state.passphraseScore = await ratePassphrase(state.passphrase);
+    if (state.passphraseScore < 3) {
+      state.error = 'Passphrase is too weak (zxcvbn score must be ≥ 3).';
+      render();
+      return;
+    }
     if (state.passphrase !== state.passphraseConfirm) {
       state.error = 'Passphrases do not match';
       render();
@@ -380,58 +431,41 @@ function attachStep3(): void {
     try {
       const w = await loadWasm();
 
-      // 1. Generate 32-byte image secret
+      // 1. Generate 32-byte image secret.
       const imageSecret = new Uint8Array(32);
       crypto.getRandomValues(imageSecret);
 
-      // 2. Embed secret into carrier JPEG
+      // 2. Embed secret into carrier JPEG.
       state.referenceImageBytes = new Uint8Array(
-        w.embed_image_secret(state.carrierImageBytes, imageSecret)
+        w.embed_image_secret(state.carrierImageBytes, imageSecret),
       );
 
-      // 3. Generate 32-byte salt
+      // 3. Generate 32-byte salt + KDF params.
       const salt = new Uint8Array(32);
       crypto.getRandomValues(salt);
-
-      // 4. Create KDF params
       const paramsJson = '{"argon2_m":65536,"argon2_t":3,"argon2_p":4}';
 
-      // 5. Derive master key
-      const masterKey = w.derive_master_key(
-        state.passphrase,
-        imageSecret,
-        salt,
-        paramsJson,
-      );
+      // 4. Derive a session handle via the typed-item unlock API.
+      //    (Single-shot master_key derivation is no longer exposed; the
+      //    handle is the only in-JS reference to the master key.)
+      const handle = w.unlock(state.passphrase, imageSecret, salt, paramsJson);
 
-      // 6. Encrypt empty manifest
-      const manifestJson = '{"entries":{},"version":1}';
-      const encryptedManifest = w.encrypt_manifest(manifestJson, masterKey);
+      // 5. Encrypt an empty schema-v2 manifest.
+      const manifestJson = '{"schema_version":2,"items":{}}';
+      const encryptedManifest = w.manifest_encrypt(handle, manifestJson);
 
-      // 7. Push vault files via git API
+      // 6. Push vault files via git API.
       const hostUrl = state.hostType === 'github' ? 'https://api.github.com' : state.hostUrl;
       const host = createGitHost(state.hostType, hostUrl, state.repoPath, state.apiToken);
 
-      await host.writeFile(
-        '.relicario/salt',
-        salt,
-        'init: vault salt',
-      );
+      await host.writeFile('.relicario/salt', salt, 'init: vault salt');
 
       const paramsBytes = new TextEncoder().encode(paramsJson);
-      await host.writeFile(
-        '.relicario/params.json',
-        paramsBytes,
-        'init: KDF parameters',
-      );
+      await host.writeFile('.relicario/params.json', paramsBytes, 'init: KDF parameters');
 
       const devicesJson = '{"devices":[]}';
       const devicesBytes = new TextEncoder().encode(devicesJson);
-      await host.writeFile(
-        '.relicario/devices.json',
-        devicesBytes,
-        'init: device registry',
-      );
+      await host.writeFile('.relicario/devices.json', devicesBytes, 'init: device registry');
 
       await host.writeFile(
         'manifest.enc',
@@ -439,12 +473,15 @@ function attachStep3(): void {
         'init: encrypted manifest',
       );
 
-      // 8. Advance to step 4
+      // 7. Release the handle — the SW's own unlock will re-derive.
+      w.lock(handle);
+
+      // 8. Advance to step 4.
       state.creating = false;
       state.step = 4;
       state.error = null;
 
-      // Detect extension
+      // Detect extension.
       detectExtension();
 
       render();

extension/src/wasm.d.ts

@@ -1,7 +1,13 @@
 // Thin TypeScript declarations for the relicario-wasm bindings.
 // These are hand-written to mirror the #[wasm_bindgen] signatures in
 // crates/relicario-wasm/src/lib.rs; keep them in sync manually.
+//
+// Declared under the bare specifier 'relicario-wasm' so `typeof
+// import('relicario-wasm')` resolves in setup.ts. Webpack doesn't
+// actually resolve the module — setup.ts loads the auto-generated
+// wasm/relicario_wasm.js via a webpackIgnore dynamic import at runtime.
 
+declare module 'relicario-wasm' {
   export class SessionHandle {
     readonly value: number;
     free(): void;
@@ -54,8 +60,6 @@ export function embed_image_secret(carrier: Uint8Array, secret: Uint8Array): Uin
 
   export function totp_compute(config_json: string, now_unix_seconds: bigint): TotpCode;
 
-// Initializer (wasm-bindgen's default init function).
   export default function init(module_or_path?: unknown): Promise<void>;
-
-// wasm-bindgen's sync init — Chrome MV3 service workers can't use dynamic import().
   export function initSync(args: { module: WebAssembly.Module }): void;
+}

extension/tsconfig.json

@@ -9,9 +9,6 @@
     "rootDir": "./src",
     "sourceMap": true,
     "lib": ["ES2022", "DOM", "DOM.Iterable"],
-    "paths": {
-      "relicario-wasm": ["./wasm/relicario_wasm.js"]
-    },
     "baseUrl": "."
   },
   "include": ["src/**/*"],