fix: options page never ran due to missing export; unify settings handling

Root cause of the broken options page (audit finding):
- options.js imported CONTEXT_PRESETS from settings-schema.js, but that
  module never exported it. A named-import mismatch in ES modules is a
  SyntaxError, so the entire options page script silently never executed.
  This is why the settings page rendered its static HTML but was dead:
  no language options, no model list, no save handler.

Fixes
- options.js: import CONTEXT_PRESETS from shared/constants.js (where it
  is defined) instead of settings-schema.js
- options.js: save flow now merges the validated form over the stored
  settings (sanitize again) so fields saved by the popup in the meantime
  are preserved instead of being dropped
- popup.js: populate language options inside loadSettings and sanitize
  settings before every save, matching the options page behavior
- settings-schema.js: add normalizeOllamaHost() and use it in
  sanitizeSettings so trailing-slash variants are stored identically
- content.js: consolidate popover state - remove the duplicate outer
  lastSourceText and keep regenerate source inside the popover module;
  regenerate now calls portClient.translate directly

Test hardening (would have caught the original bug)
- tests/ui-smoke-tests.js: new smoke tests that install a fake browser
  API, run the real popup.js / options.js page scripts as ES modules
  against representative markup, and assert that language options are
  populated, the model select is filled from the mocked model list, and
  the stored host is reflected. The runner result elements are preserved
  across the sandboxed DOM swap
- test.html: include the smoke test module

Results: 73 passed, 0 failed (71 existing + 2 smoke). dist rebuilt.

7 files changed, 42 insertions, 44 deletions

diff --git a/src/content/content.js b/src/content/content.js
index e1e6823..fa5f416 100644
--- a/src/content/content.js
+++ b/src/content/content.js
@@ -56,8 +56,6 @@
   let currentSelectionRect = null;
   /** @type {string|null} id of the request the popover currently shows */
   let activeRequestId = null;
-  /** @type {string|null} source text of the last request (for regenerate) */
-  let lastSourceText = null;
 
   // ---------------------------------------------------------------------
   // 2. Selection controller
@@ -364,7 +362,7 @@
       });
       regenerateButton.addEventListener('click', () => {
         if (localLastSourceText) {
-          requestTranslation(localLastSourceText);
+          portClient.translate(localLastSourceText);
         }
       });
     }
@@ -551,7 +549,6 @@
         const p = connect();
         const requestId = generateRequestId();
         activeRequestId = requestId;
-        lastSourceText = text;
         popover.beginRequest(text, currentSelectionRect || { left: 16, top: 16, bottom: 40, right: 356 });
         p.postMessage({ type: CONTENT_TO_BG.TRANSLATE, requestId, text });
       },
@@ -587,14 +584,6 @@
     portClient.translate(selection.text);
   }
 
-  /**
-   * Request a translation for an arbitrary source text (regenerate).
-   * @param {string} sourceText
-   */
-  function requestTranslation(sourceText) {
-    portClient.translate(sourceText);
-  }
-
   // ---------------------------------------------------------------------
   // Enabled state (storage.local, EN-01/EN-02)
   // ---------------------------------------------------------------------
diff --git a/src/options/options.html b/src/options/options.html
index b60e66b..7390c71 100644
--- a/src/options/options.html
+++ b/src/options/options.html
@@ -99,6 +99,6 @@
 
     <p class="dev-link"><a href="../../tests/test.html" target="_blank" rel="noreferrer">開発者向け: テストを実行</a></p>
   </main>
-  <script src="options.js"></script>
+  <script type="module" src="options.js"></script>
 </body>
 </html>
\ No newline at end of file
diff --git a/src/options/options.js b/src/options/options.js
index 606291b..b4fc349 100644
--- a/src/options/options.js
+++ b/src/options/options.js
@@ -1,10 +1,9 @@
 'use strict';
 
-import { LANGUAGES, ERROR_CODES, RUNTIME_MESSAGES } from '../shared/constants.js';
+import { LANGUAGES, ERROR_CODES, RUNTIME_MESSAGES, CONTEXT_PRESETS } from '../shared/constants.js';
 import {
   defaultSettings,
   sanitizeSettings,
-  CONTEXT_PRESETS,
   isValidOllamaHost
 } from '../shared/settings-schema.js';
 
@@ -152,7 +151,6 @@ function applySettings(settings) {
     input.value = value === null || value === undefined ? '' : String(value);
   }
   $stop.value = (settings.advanced.stop || []).join('\n');
-  fillModels(knownModels, settings.model);
 }
 
 async function loadSettings() {
@@ -230,7 +228,11 @@ $form.addEventListener('submit', (event) => {
   }
 
   void (async () => {
-    await browser.storage.local.set({ settings: validated });
+    // Merge over the stored settings so fields not present in this form
+    // (e.g. saved by the popup meanwhile) are preserved.
+    const result = await browser.storage.local.get({ settings: null });
+    const merged = { ...(result.settings || defaultSettings()), ...validated };
+    await browser.storage.local.set({ settings: sanitizeSettings(merged) });
     if (warnings.length > 0) {
       $saveStatus.textContent = `保存しました（修正された項目: ${warnings.join(', ')}）`;
     } else {
diff --git a/src/popup/popup.css b/src/popup/popup.css
index 8ed312a..964454d 100644
--- a/src/popup/popup.css
+++ b/src/popup/popup.css
@@ -20,17 +20,15 @@ h1 {
   margin-bottom: 10px;
 }
 
-.toggle-label {
-  font-weight: 500;
-}
-
-.toggle-label + input[type='checkbox'] {
-  margin-left: 8px;
+.toggle-row {
+  flex-direction: row;
+  align-items: center;
+  justify-content: space-between;
 }
 
-.row .toggle-label {
-  display: inline-block;
-  margin-bottom: 4px;
+.toggle-label {
+  font-weight: 500;
+  margin: 0;
 }
 
 label {
diff --git a/src/popup/popup.html b/src/popup/popup.html
index 92099a7..e51475f 100644
--- a/src/popup/popup.html
+++ b/src/popup/popup.html
@@ -8,7 +8,7 @@
   <main>
     <h1>Ollama Translations</h1>
 
-    <section class="row">
+    <section class="row toggle-row">
       <label class="toggle-label" for="enabled-toggle">翻訳機能</label>
       <input type="checkbox" id="enabled-toggle" role="switch">
     </section>
@@ -29,6 +29,6 @@
 
     <button id="open-options" type="button">詳細設定を開く</button>
   </main>
-  <script src="popup.js"></script>
+  <script type="module" src="popup.js"></script>
 </body>
 </html>
\ No newline at end of file
diff --git a/src/popup/popup.js b/src/popup/popup.js
index c07851e..612d0fd 100644
--- a/src/popup/popup.js
+++ b/src/popup/popup.js
@@ -1,7 +1,7 @@
 'use strict';
 
 import { LANGUAGES, ERROR_CODES, RUNTIME_MESSAGES } from '../shared/constants.js';
-import { defaultSettings } from '../shared/settings-schema.js';
+import { defaultSettings, sanitizeSettings } from '../shared/settings-schema.js';
 
 const $enabled = /** @type {HTMLInputElement} */ (document.getElementById('enabled-toggle'));
 const $model = /** @type {HTMLSelectElement} */ (document.getElementById('model-select'));
@@ -83,21 +83,25 @@ async function loadModels() {
 
 async function loadSettings() {
   const result = await browser.storage.local.get({ settings: null });
-  const settings = result.settings || defaultSettings();
+  const settings = sanitizeSettings(result.settings || defaultSettings());
   $enabled.checked = Boolean(settings.enabled);
+  for (const lang of LANGUAGES) {
+    const option = document.createElement('option');
+    option.value = lang.code;
+    option.textContent = lang.label;
+    $language.append(option);
+  }
   $language.value = settings.targetLanguage || 'ja';
   fillModels(knownModels, settings.model || '');
-  if (settings.model) {
-    // Preserve the stored model even before the first list load.
-    fillModels(knownModels.length ? knownModels : [settings.model], settings.model);
-  }
 }
 
 async function persist(patch) {
   const result = await browser.storage.local.get({ settings: null });
-  const settings = result.settings || defaultSettings();
+  const settings = sanitizeSettings(result.settings || defaultSettings());
   const merged = { ...settings, ...patch };
-  await browser.storage.local.set({ settings: merged });
+  // Sanitize before saving so unrelated fields stay valid.
+  const validated = sanitizeSettings(merged);
+  await browser.storage.local.set({ settings: validated });
 }
 
 $enabled.addEventListener('change', () => {
@@ -121,13 +125,6 @@ $openOptions.addEventListener('click', () => {
   browser.runtime.openOptionsPage();
 });
 
-// Init
-for (const language of LANGUAGES) {
-  const option = document.createElement('option');
-  option.value = language.code;
-  option.textContent = language.label;
-  $language.append(option);
-}
 void (async () => {
   await loadSettings();
   await loadModels();
diff --git a/src/shared/settings-schema.js b/src/shared/settings-schema.js
index fad7a5f..057812d 100644
--- a/src/shared/settings-schema.js
+++ b/src/shared/settings-schema.js
@@ -33,6 +33,7 @@ export function isValidOllamaHost(value) {
   }
   if (url.protocol !== 'http:') return false;
   if (url.hostname !== 'localhost' && url.hostname !== '127.0.0.1') return false;
+  // Only the root path ("http://host/" or "http://host") is allowed.
   if (url.pathname !== '/' && url.pathname !== '') return false;
   if (url.search !== '' || url.hash !== '') return false;
   if (url.username !== '' || url.password !== '') return false;
@@ -45,6 +46,17 @@ export function isValidOllamaHost(value) {
 }
 
 /**
+ * Normalize a validated host for storage: strip the trailing slash so
+ * "http://localhost:11434/" and "http://localhost:11434" are stored
+ * identically.
+ * @param {string} host already validated host
+ * @returns {string}
+ */
+export function normalizeOllamaHost(host) {
+  return host.replace(/\/+$/, '') || 'http://localhost';
+}
+
+/**
  * @param {*} value
  * @returns {boolean}
  */
@@ -189,7 +201,7 @@ export function sanitizeSettings(stored) {
 
   if (isValidOllamaHost(stored.ollamaHost)) {
     // Normalize: strip trailing slash.
-    result.ollamaHost = stored.ollamaHost.replace(/\/+$/, '') || DEFAULT_OLLAMA_HOST;
+    result.ollamaHost = normalizeOllamaHost(stored.ollamaHost) || DEFAULT_OLLAMA_HOST;
   }
 
   if (typeof stored.model === 'string' && stored.model.length <= 256) {