feat: custom secret patterns + rename Secret Scanner → Auto Redact

Users can now define custom regex patterns for proprietary token formats,
internal URLs with keys, or any secret the built-in scanner doesn't cover.
Patterns are added/toggled/removed from the Options page and apply to both
the live interception (content.js) and the Test tab (popup.js).

Renamed all user-facing "Secret scanning" labels to "Auto Redact" across
popup and options. Internal variable names (secretScanning, SecretScanner)
kept for backwards compatibility with stored settings.

https://claude.ai/code/session_01KF4i7Ra7zCEDskxDBaNtcT

src/options/options.js

@@ -297,6 +297,13 @@ document.addEventListener('DOMContentLoaded', async () => {
     await Storage.saveSettings({ secretScanning: e.target.checked });
   });
 
+  // Custom secret patterns
+  renderCustomSecrets();
+  $('#btnAddSecretPattern').addEventListener('click', addCustomSecret);
+  $('#newSecretPattern').addEventListener('keydown', (e) => {
+    if (e.key === 'Enter') addCustomSecret();
+  });
+
   $('#autoDetect').addEventListener('change', async (e) => {
     await Storage.saveSettings({ autoDetect: e.target.checked });
   });
@@ -798,6 +805,90 @@ function renderDomains() {
   });
 }
 
+// --- Custom Secret Patterns ---
+
+function addCustomSecret() {
+  const name = $('#newSecretName').value.trim();
+  const pattern = $('#newSecretPattern').value.trim();
+  const redact = $('#newSecretRedact').value.trim();
+
+  if (!pattern) { alert('Pattern is required.'); return; }
+
+  // Validate regex
+  try {
+    new RegExp(pattern, 'g');
+  } catch (e) {
+    alert('Invalid regex: ' + e.message);
+    return;
+  }
+
+  const label = name || 'Custom Pattern';
+  const replacement = redact || `[REDACTED-${label.toUpperCase().replace(/\s+/g, '-')}]`;
+
+  const patterns = settings.customSecretPatterns || [];
+  patterns.push({
+    id: crypto.randomUUID(),
+    name: label,
+    pattern,
+    redact: replacement,
+    enabled: true,
+  });
+
+  settings.customSecretPatterns = patterns;
+  Storage.saveSettings({ customSecretPatterns: patterns });
+  renderCustomSecrets();
+
+  $('#newSecretName').value = '';
+  $('#newSecretPattern').value = '';
+  $('#newSecretRedact').value = '';
+}
+
+function renderCustomSecrets() {
+  const list = $('#customSecretList');
+  if (!list) return;
+  const patterns = settings.customSecretPatterns || [];
+
+  if (patterns.length === 0) {
+    safeHTML(list, '<div style="font-size:12px;color:#9ca3af;padding:6px 0">No custom patterns defined. Built-in patterns cover common API keys, tokens, and credentials.</div>');
+    return;
+  }
+
+  safeHTML(list, patterns.map((p, i) => `
+    <div style="display:flex;align-items:center;gap:6px;padding:6px 8px;background:#fff;border:1px solid #e5e7eb;border-radius:6px;margin-bottom:4px;flex-wrap:wrap">
+      <label style="display:flex;align-items:center;gap:4px;cursor:pointer;min-width:0">
+        <input type="checkbox" class="secret-toggle" data-index="${i}" ${p.enabled ? 'checked' : ''}>
+      </label>
+      <span style="font-size:12px;font-weight:500;white-space:nowrap">${escapeHtml(p.name)}</span>
+      <code style="font-size:11px;color:#6b7280;background:#f3f4f6;padding:1px 5px;border-radius:3px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;max-width:250px" title="${escapeHtml(p.pattern)}">${escapeHtml(p.pattern)}</code>
+      <span style="font-size:11px;color:#9ca3af;margin-left:auto;white-space:nowrap">&rarr; ${escapeHtml(p.redact)}</span>
+      <button class="btn btn-sm btn-danger btn-remove-secret" data-index="${i}" style="padding:2px 6px">&times;</button>
+    </div>
+  `).join(''));
+
+  // Toggle handlers
+  list.querySelectorAll('.secret-toggle').forEach(toggle => {
+    toggle.addEventListener('change', async () => {
+      const idx = parseInt(toggle.dataset.index, 10);
+      const patterns = settings.customSecretPatterns || [];
+      patterns[idx].enabled = toggle.checked;
+      settings.customSecretPatterns = patterns;
+      await Storage.saveSettings({ customSecretPatterns: patterns });
+    });
+  });
+
+  // Remove handlers
+  list.querySelectorAll('.btn-remove-secret').forEach(btn => {
+    btn.addEventListener('click', async () => {
+      const idx = parseInt(btn.dataset.index, 10);
+      const patterns = settings.customSecretPatterns || [];
+      patterns.splice(idx, 1);
+      settings.customSecretPatterns = patterns;
+      await Storage.saveSettings({ customSecretPatterns: patterns });
+      renderCustomSecrets();
+    });
+  });
+}
+
 // --- Transfer Data (Export/Import All) ---
 
 async function getAllData() {