feat: Options tab in popup + Safari build script

Popup:
- Added 5th "Options" tab with key settings accessible without
  opening the full options page: secret scanning, auto-detect PPI,
  auto-redact, show highlights, document scan preview
- "Open Full Options Page" button for sync/encryption/org/import
- Settings changes in popup immediately broadcast to content scripts

Safari:
- Added build-safari.sh that uses Apple's safari-web-extension-converter
  to generate an Xcode project from the Firefox build
- browser-polyfill.js already handles Safari (uses browser.* like Firefox)

https://claude.ai/code/session_01SWSwDfMVij53bCTNSCLMwn

src/popup/popup.js

@@ -208,12 +208,40 @@ async function initUnlockedUI() {
     });
   });
 
-  // Options link
+  // Options link (footer)
   $('#btnOptions').addEventListener('click', (e) => {
     e.preventDefault();
     api.runtime.openOptionsPage();
   });
 
+  // Options tab
+  $('#btnOpenFullOptions').addEventListener('click', () => {
+    api.runtime.openOptionsPage();
+  });
+
+  // Load options tab settings
+  $('#optSecretScanning').checked = settings.secretScanning !== false;
+  $('#optAutoDetect').checked = settings.autoDetect !== false;
+  $('#optAutoRedact').checked = settings.autoRedactDetected !== false;
+  $('#optHighlights').checked = settings.showHighlights || false;
+  $('#optDocPreview').checked = settings.docScanPreview !== false;
+
+  // Options tab change handlers
+  const optHandlers = [
+    ['optSecretScanning', 'secretScanning'],
+    ['optAutoDetect', 'autoDetect'],
+    ['optAutoRedact', 'autoRedactDetected'],
+    ['optHighlights', 'showHighlights'],
+    ['optDocPreview', 'docScanPreview'],
+  ];
+  for (const [id, key] of optHandlers) {
+    $(`#${id}`).addEventListener('change', async (e) => {
+      settings[key] = e.target.checked;
+      await Storage.saveSettings({ [key]: e.target.checked });
+      api.runtime.sendMessage({ type: 'update:settings', settings });
+    });
+  }
+
   // Update privacy note based on encryption state
   const encEnabled = await Storage._isAtRestEncryptionEnabled();
   const encNote = $('#privacyEncNote');