feat: custom domains for OpenWebUI + fix README issues

- Add custom domain support in Options page so users can add
  self-hosted AI services (e.g. https://ai.myserver.com)
- Background worker dynamically injects content scripts on
  custom domains using scripting.executeScript
- Add optional_host_permissions so Chrome can grant per-domain access
- Rewrite README: add clone step to Firefox instructions, clarify
  what "credentials" means in step 3, add Windows commands alongside
  Mac/Linux for every terminal step
- Bump version to 0.2.0

https://claude.ai/code/session_01Dvgwe7XMoSxnWXkih8p1Cw

src/options/options.html

@@ -79,6 +79,19 @@
       </div>
     </section>
 
+    <section class="section">
+      <h2>Custom Domains</h2>
+      <p class="section-desc">Add domains for self-hosted AI services (like OpenWebUI). The extension will activate on these domains in addition to the built-in ones.</p>
+      <div class="domain-list" id="domainList"></div>
+      <div class="add-row">
+        <input type="text" id="newDomain" placeholder="https://ai.myserver.com" class="input" style="flex:2">
+        <button class="btn btn-primary" id="btnAddDomain">Add Domain</button>
+      </div>
+      <p class="section-desc" style="margin-top:8px;margin-bottom:0">
+        After adding a domain in Chrome, you also need to grant permission: <code>chrome://extensions/</code> → Silent Send → Details → Site access → add the domain.
+      </p>
+    </section>
+
     <section class="section">
       <h2>Activity Log</h2>
       <div class="log-actions">
@@ -89,7 +102,7 @@
     </section>
 
     <footer>
-      <p>Silent Send v0.1.0</p>
+      <p>Silent Send v0.2.0</p>
     </footer>
   </div>
 

src/options/options.js

@@ -14,8 +14,15 @@ document.addEventListener('DOMContentLoaded', async () => {
   $('#maxLogEntries').value = settings.maxLogEntries || 200;
 
   renderMappings();
+  renderDomains();
   renderLog();
 
+  // Custom domains
+  $('#btnAddDomain').addEventListener('click', addDomain);
+  $('#newDomain').addEventListener('keydown', (e) => {
+    if (e.key === 'Enter') addDomain();
+  });
+
   // Settings listeners
   $('#showHighlights').addEventListener('change', async (e) => {
     await Storage.saveSettings({ showHighlights: e.target.checked });
@@ -176,6 +183,61 @@ async function renderLog() {
     .join('');
 }
 
+// --- Custom Domains ---
+async function addDomain() {
+  let domain = $('#newDomain').value.trim();
+  if (!domain) return;
+
+  // Normalize: ensure it has a protocol
+  if (!domain.startsWith('http://') && !domain.startsWith('https://')) {
+    domain = 'https://' + domain;
+  }
+  // Strip trailing slashes
+  domain = domain.replace(/\/+$/, '');
+
+  const domains = settings.customDomains || [];
+  if (domains.includes(domain)) {
+    alert('Domain already added.');
+    return;
+  }
+
+  domains.push(domain);
+  settings.customDomains = domains;
+  await Storage.saveSettings({ customDomains: domains });
+  renderDomains();
+  $('#newDomain').value = '';
+}
+
+function renderDomains() {
+  const list = $('#domainList');
+  const domains = settings.customDomains || [];
+
+  if (domains.length === 0) {
+    list.innerHTML = '<div style="text-align:center;color:#9ca3af;padding:12px;font-size:13px">No custom domains. Built-in sites (Claude, ChatGPT, Grok, Gemini, localhost) are always active.</div>';
+    return;
+  }
+
+  list.innerHTML = domains
+    .map((d, i) => `
+      <div class="domain-item" style="display:flex;align-items:center;justify-content:space-between;padding:8px;background:#f9fafb;border-radius:6px;margin-bottom:4px">
+        <span style="font-size:13px;font-family:monospace">${escapeHtml(d)}</span>
+        <button class="btn btn-sm btn-danger btn-remove-domain" data-index="${i}">&times;</button>
+      </div>
+    `)
+    .join('');
+
+  list.querySelectorAll('.btn-remove-domain').forEach((btn) => {
+    btn.addEventListener('click', async () => {
+      const idx = parseInt(btn.dataset.index, 10);
+      const domains = settings.customDomains || [];
+      domains.splice(idx, 1);
+      settings.customDomains = domains;
+      await Storage.saveSettings({ customDomains: domains });
+      renderDomains();
+    });
+  });
+}
+
 function escapeHtml(str) {
   const div = document.createElement('div');
   div.textContent = str;