feat(generator): add personalized Random Idea button powered by background profile + Whack Pack card + Codex

public/index.html

@@ -39,8 +39,16 @@
       <button type="submit" class="btn btn-primary btn-sm">Capture</button>
       <button
         type="button"
-        id="btn-open-external-clip"
+        id="btn-generate-random-idea"
         class="btn btn-secondary btn-sm"
+        title="Generate a personalized random idea tailored to your background & a Whack Pack card"
+      >
+        🎲 Random Idea
+      </button>
+      <button
+        type="button"
+        id="btn-open-external-clip"
+        class="btn btn-ghost btn-sm"
         title="Attach external notes, clipboard screenshots, photos, or image URLs to a spark"
       >
         📎 Clip / Attach
@@ -750,6 +758,16 @@
             <option value="gemini-3.1-flash-lite-image">gemini-3.1-flash-lite-image — Nano Banana 2 Lite (Ultra-Fast)</option>
           </select>
         </div>
+        <div class="field-group">
+          <label for="settings-user-background">🎲 Personal Background & Tastes (Used by '🎲 Random Idea')</label>
+          <textarea
+            id="settings-user-background"
+            rows="5"
+            class="textarea-input"
+            placeholder="Describe your interests, aesthetic tastes, homelab stack, apparel preferences..."
+          ></textarea>
+          <small class="muted-label">When you click <strong>🎲 Random Idea</strong>, SparkVault combines this profile with a random Creative Whack Pack card to invent a tailored idea.</small>
+        </div>
         <div class="modal-footer">
           <button type="button" id="btn-cancel-settings" class="btn btn-ghost">Cancel</button>
           <button type="submit" class="btn btn-primary">Save Settings</button>