Support multiple photos per event

photoId now holds one or more photo UUIDs, comma-separated. The server
never interprets the field (photos are uploaded and served individually
by UUID), so no schema change is needed and legacy single-photo events
are already valid one-element lists.

Both dialogs let you keep adding photos, previewed as thumbnails with a
per-photo remove button; the file input allows multi-select and no
longer forces the camera, so the gallery is available too. History rows
show every photo, each opening in the lightbox.

src/index.html

@@ -332,9 +332,8 @@
           <textarea id="note-input" rows="4" placeholder="e.g. pee was instant, poo took 5min, ate 300g raw food"></textarea>
         </label>
         <div class="photo-field">
-          <input type="file" id="note-photo-input" accept="image/*" capture="environment" hidden />
-          <button type="button" id="note-photo-btn" class="ghost">📷 Add photo</button>
-          <button type="button" id="note-photo-clear" class="ghost" hidden>Remove photo</button>
+          <input type="file" id="note-photo-input" accept="image/*" multiple hidden />
+          <button type="button" id="note-photo-btn" class="ghost">📷 Add photos</button>
           <div id="note-photo-preview" class="photo-preview" hidden></div>
         </div>
         <menu>
@@ -363,9 +362,8 @@
           <textarea id="edit-note" rows="4"></textarea>
         </label>
         <div class="photo-field">
-          <input type="file" id="edit-photo-input" accept="image/*" capture="environment" hidden />
-          <button type="button" id="edit-photo-btn" class="ghost">📷 Add photo</button>
-          <button type="button" id="edit-photo-clear" class="ghost" hidden>Remove photo</button>
+          <input type="file" id="edit-photo-input" accept="image/*" multiple hidden />
+          <button type="button" id="edit-photo-btn" class="ghost">📷 Add photos</button>
           <div id="edit-photo-preview" class="photo-preview" hidden></div>
         </div>
         <menu>