fix(reauth): wrong master pw re-prompts inline instead of closing

Setting a PIN, enabling Quick Unlock, and generating a recovery key all
closed the reauth modal and showed a toast on the first wrong master
password — no retry. Export already looped inline; the others didn't.

Extracted that loop into reauthLoop(message): re-prompts with an inline
error + attempt count (5 tries), honours the 429 lockout, returns the
verified password or null. All four sensitive-action flows now share it, so
a mistyped master password keeps the modal up to try again.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

js/app.import.js

@@ -791,39 +791,10 @@ async function doExport() {
     // Step 1: reauth — verifies the human in front of the screen is the
     // vault owner before we hand them every plaintext password. Defense
     // against a stranger reaching the open laptop and exfiltrating data.
-    // Up to 5 retries with inline error in the modal — beyond that the
-    // server-side rate limiter takes over (429 with retry_after).
-    let lastError = null;
-    let attempts = 0;
-    const MAX_ATTEMPTS = 5;
-    let reauthed = false;
-    while (!reauthed) {
-        const masterPwd = await askReauth(
-            'Enter your master password to start an encrypted export.',
-            { error: lastError });
-        if (!masterPwd) return;   // user cancelled
-        try {
-            const verifier = await computeVerifier(
-                masterPwd, state.salt, state.kdfIterations || 100000, state.hashAlgo, state.argon2Params);
-            await api('/reauth', {
-                method: 'POST',
-                headers: authHeaders({ 'Content-Type': 'application/json' }),
-                body: JSON.stringify({ verifier: verifier }),
-            });
-            reauthed = true;
-        } catch (err) {
-            if (err.status === 429 && err.body && err.body.retry_after) {
-                return toast('Account locked. Try again in ' +
-                    Math.ceil(err.body.retry_after / 60) + ' min', 'warning');
-            }
-            attempts++;
-            if (attempts >= MAX_ATTEMPTS) {
-                return toast('Too many wrong attempts — try again later', 'error');
-            }
-            lastError = 'Wrong master password. Attempt ' +
-                attempts + ' / ' + MAX_ATTEMPTS + '.';
-        }
-    }
+    // reauthLoop re-prompts inline (up to 5 tries) then defers to the
+    // server rate limiter; null = cancelled or capped (already toasted).
+    if (!(await reauthLoop('Enter your master password to start an encrypted export.')))
+        return;
 
     // Step 2: ask for an INDEPENDENT export password. Decoupled from the
     // master pw so a master-pw change later doesn't invalidate the backup,

js/app.js

@@ -6022,6 +6022,45 @@ function closeReauth(ok) {
     }
 }
 
+// Prompt for the master password and verify it via /reauth, RE-PROMPTING
+// inline on a wrong entry (the modal stays up with an error + attempt count)
+// instead of closing on the first miss. The single choke point for every
+// sensitive-action reauth (export, PIN set, Quick Unlock, recovery) so they
+// all behave the same. Returns the verified master password, or null when the
+// user cancels or the attempt cap / server lockout is hit (already toasted).
+async function reauthLoop(message) {
+    const MAX = 5;
+    let attempts = 0;
+    let lastError = '';
+    for (;;) {
+        const pwd = await askReauth(message, { error: lastError });
+        if (!pwd) return null;   // cancelled
+        try {
+            const verifier = await computeVerifier(
+                pwd, state.salt, state.kdfIterations || 100000,
+                state.hashAlgo, state.argon2Params);
+            await api('/reauth', {
+                method: 'POST',
+                headers: authHeaders({ 'Content-Type': 'application/json' }),
+                body: JSON.stringify({ verifier }),
+            });
+            return pwd;
+        } catch (err) {
+            if (err.status === 429 && err.body && err.body.retry_after) {
+                toast('Account locked. Try again in ' +
+                    Math.ceil(err.body.retry_after / 60) + ' min', 'warning');
+                return null;
+            }
+            attempts++;
+            if (attempts >= MAX) {
+                toast('Too many wrong attempts — try again later', 'error');
+                return null;
+            }
+            lastError = 'Wrong master password. Attempt ' + attempts + ' / ' + MAX + '.';
+        }
+    }
+}
+
 // ============================================================
 // QUICK UNLOCK + PIN + RECOVERY KEY — extracted to js/app.unlock.js (§3.1),
 // loaded AFTER this file (it assigns Bridge.onQuickUnlockResult / onPinResult

js/app.unlock.js

@@ -277,20 +277,9 @@ async function pinSetupFlow() {
     // Setting/changing a PIN creates a new unlock path → treat as a
     // sensitive operation. An unattended unlocked vault must not be
     // possible for a passerby to pin-backdoor.
-    const masterPwd = await askReauth(
+    const masterPwd = await reauthLoop(
         'Confirm your master password to set or change the PIN.');
     if (!masterPwd) return;
-    try {
-        const verifier = await computeVerifier(
-            masterPwd, state.salt, state.kdfIterations || 100000, state.hashAlgo, state.argon2Params);
-        await api('/reauth', {
-            method: 'POST',
-            headers: authHeaders({ 'Content-Type': 'application/json' }),
-            body: JSON.stringify({ verifier: verifier }),
-        });
-    } catch (err) {
-        return toast('Wrong master password', 'error');
-    }
 
     let lastError = '';
     let attempts = 0;
@@ -419,20 +408,9 @@ async function enableQuickUnlock() {
     if (!Bridge.active) return toast('Quick unlock requires the Delphi app', 'warning');
     if (!state.cryptoKey) return toast('Unlock the vault first', 'warning');
 
-    const masterPwd = await askReauth(
+    const masterPwd = await reauthLoop(
         'Confirm your master password to enable Quick unlock on this device.');
     if (!masterPwd) return;
-    try {
-        const verifier = await computeVerifier(
-            masterPwd, state.salt, state.kdfIterations || 100000, state.hashAlgo, state.argon2Params);
-        await api('/reauth', {
-            method: 'POST',
-            headers: authHeaders({ 'Content-Type': 'application/json' }),
-            body: JSON.stringify({ verifier: verifier }),
-        });
-    } catch (err) {
-        return toast('Wrong master password', 'error');
-    }
 
     // Export the raw key + identity. We don't store the session token —
     // tryQuickUnlock re-logs in with a verifier derived from the key,
@@ -674,7 +652,10 @@ async function unwrapAesKeyFromRecovery(wrappedKeyB64, wrappedIvB64, recoveryCod
 async function doGenerateRecoveryKey() {
     if (!state.cryptoKey) { return toast('Vault locked', 'warning'); }
 
-    const masterPwd = await askReauth(
+    // Pre-verify via reauthLoop (inline retry) so a wrong master pw re-prompts
+    // instead of failing the setup POST and closing the modal. The setup call
+    // below still carries the verifier — the server re-checks it.
+    const masterPwd = await reauthLoop(
         'Confirm your master password to generate a recovery key.');
     if (!masterPwd) return;