feat: pre-send PPI detection — warns while typing, auto-add mappings

Like spellcheck for privacy. Scans text as you type and paste
into chat inputs (debounced 800ms). Shows a dark floating warning
panel listing detected PPI BEFORE you hit Enter.

Each detected item has a green [+] button that instantly:
1. Generates a plausible fake value (random IP, fake address, etc.)
2. Adds it as a mapping to storage
3. Shows a checkmark to confirm

The warning disappears when you clear the text or when all
detected items have been addressed.

Three new Options toggles:
- Auto-detect unconfigured PPI (on by default)
- Offer to auto-add detected PPI (on by default)

Also adds a storage bridge (postMessage) so the page-world
content script can read/write chrome.storage through the
injector.

https://claude.ai/code/session_01Dvgwe7XMoSxnWXkih8p1Cw

src/options/options.html

@@ -67,6 +67,16 @@
           <span class="toggle-slider"></span>
         </label>
       </div>
+      <div class="setting-row">
+        <div>
+          <label>Offer to auto-add detected PPI</label>
+          <p class="setting-desc">Show a + button on detected PPI to instantly create a mapping with a suggested fake value</p>
+        </div>
+        <label class="toggle">
+          <input type="checkbox" id="autoAddDetected" checked>
+          <span class="toggle-slider"></span>
+        </label>
+      </div>
       <div class="setting-row">
         <div>
           <label>Max log entries</label>

src/options/options.js

@@ -15,6 +15,7 @@ document.addEventListener('DOMContentLoaded', async () => {
   $('#showHighlights').checked = settings.showHighlights || false;
   $('#secretScanning').checked = settings.secretScanning !== false;
   $('#autoDetect').checked = settings.autoDetect !== false;
+  $('#autoAddDetected').checked = settings.autoAddDetected !== false;
   $('#maxLogEntries').value = settings.maxLogEntries || 200;
 
   renderMappings();
@@ -46,6 +47,10 @@ document.addEventListener('DOMContentLoaded', async () => {
     await Storage.saveSettings({ autoDetect: e.target.checked });
   });
 
+  $('#autoAddDetected').addEventListener('change', async (e) => {
+    await Storage.saveSettings({ autoAddDetected: e.target.checked });
+  });
+
   $('#maxLogEntries').addEventListener('change', async (e) => {
     await Storage.saveSettings({ maxLogEntries: parseInt(e.target.value, 10) || 200 });
   });