Add alt text to photo uploads

- Form field for optionally adding a description
- Publish as `imeta` `alt`
- Render as `<img>` alt when set

Fixes a placeholder being published instead. Also strips the current
placeholder if set as alt text (for existing uploads).

tests/integration/components/place-photo-upload-test.gjs

@@ -97,4 +97,27 @@ module('Integration | Component | place-photo-upload', function (hooks) {
 
     assert.dom('.photo-tag-suggestions').doesNotExist();
   });
+
+  test('it renders an optional alt text input after upload selection', async function (assert) {
+    this.place = {
+      title: 'Cafe Alpha',
+      osmId: '123',
+      osmType: 'node',
+      osmTags: { amenity: 'cafe' },
+    };
+
+    await render(
+      <template><PlacePhotoUpload @place={{this.place}} /></template>
+    );
+
+    assert.dom('#photo-alt-input').doesNotExist();
+
+    const file = new File(['test'], 'photo.jpg', { type: 'image/jpeg' });
+    await selectFile(this.element, file);
+
+    assert.dom('#photo-alt-input').exists();
+    assert
+      .dom('#photo-alt-input')
+      .hasAttribute('placeholder', 'Describe this photo');
+  });
 });

tests/unit/utils/nostr-test.js

@@ -148,6 +148,68 @@ module('Unit | Utility | nostr', function () {
     assert.strictEqual(photos[1].placeIdentifier, 'osm:node:456');
   });
 
+  test('parsePlacePhotos extracts alt text from imeta', function (assert) {
+    const events = [
+      {
+        id: 'event-1',
+        pubkey: 'pubkey-1',
+        created_at: 100,
+        tags: [
+          [
+            'imeta',
+            'url https://example.com/photo.jpg',
+            'dim 800x600',
+            'alt A sunny terrace overlooking the bay',
+          ],
+        ],
+      },
+    ];
+
+    const photos = parsePlacePhotos(events);
+
+    assert.strictEqual(photos.length, 1);
+    assert.strictEqual(photos[0].alt, 'A sunny terrace overlooking the bay');
+  });
+
+  test('parsePlacePhotos strips the legacy placeholder alt text', function (assert) {
+    const events = [
+      {
+        id: 'event-1',
+        pubkey: 'pubkey-1',
+        created_at: 100,
+        tags: [
+          [
+            'imeta',
+            'url https://example.com/photo.jpg',
+            'dim 800x600',
+            'alt A photo of a place',
+          ],
+        ],
+      },
+    ];
+
+    const photos = parsePlacePhotos(events);
+
+    assert.strictEqual(photos.length, 1);
+    assert.strictEqual(photos[0].alt, null);
+  });
+
+  test('parsePlacePhotos leaves alt null when not provided', function (assert) {
+    const events = [
+      {
+        id: 'event-1',
+        pubkey: 'pubkey-1',
+        created_at: 100,
+        tags: [['imeta', 'url https://example.com/photo.jpg', 'dim 800x600']],
+      },
+    ];
+
+    const photos = parsePlacePhotos(events);
+
+    assert.strictEqual(photos.length, 1);
+    assert.strictEqual(photos[0].alt, null);
+  });
+
   test('uniqNormalizedRelays returns normalized unique relays', function (assert) {
     const relays = uniqNormalizedRelays([
       'Relay.example.com',