feat(gallery): tag→gallery nav from modal chips (#5) + OR/exclude tag scope (#6a)

Cluster A, milestone #97. #5: clicking an image-modal tag chip's body now
closes the modal and opens the gallery filtered for that one tag (fresh
filter); ✕/kebab stay as the explicit remove/rename controls.

#6a (backend of OR/exclude filtering): gallery_service._apply_scope gains a
structured tag model — tag_or_groups (AND-of-OR: one EXISTS(tag_id IN group)
per group) + tag_exclude (NOT EXISTS(tag_id IN exclude)) — layered additively
on the existing tag_ids AND path so cursors/facets/deep-links are untouched.
Threaded through scroll/timeline/jump_cursor/facets/similar + facets common
dict; _require_single_filter rejects post_id combined with OR/exclude. API
parses tag_or (repeatable → one OR-group each) + tag_not (csv exclude).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XCUHUGQLrBrkgyk1t49kpX

tests/test_gallery_service.py

@@ -305,6 +305,93 @@ async def test_scroll_multi_tag_and(db):
     assert {i.id for i in just_a.images} == {images[0].id, images[1].id}
 
 
+@pytest.mark.asyncio
+async def test_scroll_tag_or_group(db):
+    # #6: one OR-group — match images carrying AT LEAST ONE of the group's tags.
+    images = await _seed_images(db, 3)
+    a = Tag(name="ora", kind=TagKind.general)
+    b = Tag(name="orb", kind=TagKind.general)
+    db.add_all([a, b])
+    await db.flush()
+    await db.execute(image_tag.insert().values([
+        {"image_record_id": images[0].id, "tag_id": a.id, "source": "manual"},
+        {"image_record_id": images[1].id, "tag_id": b.id, "source": "manual"},
+        # images[2] carries neither.
+    ]))
+    svc = GalleryService(db)
+    page = await svc.scroll(cursor=None, limit=10, tag_or_groups=[[a.id, b.id]])
+    assert {i.id for i in page.images} == {images[0].id, images[1].id}
+
+
+@pytest.mark.asyncio
+async def test_scroll_tag_or_groups_anded(db):
+    # Two OR-groups AND together: image must satisfy (a OR b) AND (c).
+    images = await _seed_images(db, 3)
+    a = Tag(name="aaa", kind=TagKind.general)
+    b = Tag(name="bbb", kind=TagKind.general)
+    c = Tag(name="ccc", kind=TagKind.general)
+    db.add_all([a, b, c])
+    await db.flush()
+    await db.execute(image_tag.insert().values([
+        {"image_record_id": images[0].id, "tag_id": a.id, "source": "manual"},
+        {"image_record_id": images[0].id, "tag_id": c.id, "source": "manual"},
+        {"image_record_id": images[1].id, "tag_id": b.id, "source": "manual"},
+        {"image_record_id": images[2].id, "tag_id": a.id, "source": "manual"},
+    ]))
+    svc = GalleryService(db)
+    page = await svc.scroll(
+        cursor=None, limit=10, tag_or_groups=[[a.id, b.id], [c.id]],
+    )
+    # Only images[0] has both an (a-or-b) tag AND c.
+    assert [i.id for i in page.images] == [images[0].id]
+
+
+@pytest.mark.asyncio
+async def test_scroll_tag_exclude(db):
+    # #6: exclude — drop images carrying ANY excluded tag.
+    images = await _seed_images(db, 3)
+    x = Tag(name="xxx", kind=TagKind.general)
+    db.add(x)
+    await db.flush()
+    await db.execute(image_tag.insert().values(
+        image_record_id=images[0].id, tag_id=x.id, source="manual",
+    ))
+    svc = GalleryService(db)
+    page = await svc.scroll(cursor=None, limit=10, tag_exclude=[x.id])
+    assert {i.id for i in page.images} == {images[1].id, images[2].id}
+
+
+@pytest.mark.asyncio
+async def test_scroll_or_and_exclude_compose(db):
+    # The structured model composes: (a OR b) AND NOT x.
+    images = await _seed_images(db, 3)
+    a = Tag(name="ca", kind=TagKind.general)
+    b = Tag(name="cb", kind=TagKind.general)
+    x = Tag(name="cx", kind=TagKind.general)
+    db.add_all([a, b, x])
+    await db.flush()
+    await db.execute(image_tag.insert().values([
+        {"image_record_id": images[0].id, "tag_id": a.id, "source": "manual"},
+        {"image_record_id": images[0].id, "tag_id": x.id, "source": "manual"},
+        {"image_record_id": images[1].id, "tag_id": b.id, "source": "manual"},
+    ]))
+    svc = GalleryService(db)
+    page = await svc.scroll(
+        cursor=None, limit=10, tag_or_groups=[[a.id, b.id]], tag_exclude=[x.id],
+    )
+    # images[0] matches the OR-group but is excluded by x; images[1] survives.
+    assert [i.id for i in page.images] == [images[1].id]
+
+
+@pytest.mark.asyncio
+async def test_require_single_filter_rejects_post_id_with_or_or_exclude(db):
+    svc = GalleryService(db)
+    with pytest.raises(ValueError, match="post_id cannot be combined"):
+        await svc.scroll(cursor=None, limit=10, post_id=5, tag_or_groups=[[1]])
+    with pytest.raises(ValueError, match="post_id cannot be combined"):
+        await svc.scroll(cursor=None, limit=10, post_id=5, tag_exclude=[1])
+
+
 @pytest.mark.asyncio
 async def test_scroll_media_filter(db):
     imgs = await _seed_images(db, 2)  # image/jpeg