perf(images): keep the category filter's link read narrow; record D141, D142, D145 (#332)

Under a category the link read keeps only links whose raw recipe or
positive category is the value (Python still decides the inherited
one), the links of images whose own category is the value are read by
path, and plain reads skip the inherited-category work. The own-category
map is keyed by normalized path. TESTING.md records D141, D142 and D145
and amends D13, D36 and D39; the filter budget seeds 2,000 own
categories.

tests/test_api_workspace_images.py

@@ -1529,7 +1529,9 @@ class TestWorkspaceImages(ImageAPITestCase):
         wanted = {normalize_image_path(str(files["night_ab"])), "/elsewhere/7.png"}
         elsewhere = self.api.db.get_prompt_id_for_image("/elsewhere/7.png")
         self.assertEqual(
-            self.api.db.get_image_link_matches("", [], every_link=True, wanted=wanted),
+            self.api.db.get_image_link_matches(
+                "", [], every_link=True, wanted=wanted, category="Night"
+            ),
             {
                 normalize_image_path(str(files["night_ab"])): (
                     True,
@@ -1589,6 +1591,24 @@ class TestWorkspaceImages(ImageAPITestCase):
                     for i in range(links)
                 ],
             )
+        # 2,000 images (one in 25 at 50,000 files) carry their own category
+        # (#332), so a category filter also reads and matches those.
+        from py.api.images import _favorite_root_key
+
+        root_key = _favorite_root_key(self.output_dir)
+        with self.api.db.model.get_connection() as conn:
+            conn.executemany(
+                "INSERT INTO image_categories VALUES(?,?,?,?)",
+                [
+                    (
+                        root_key,
+                        listed[i][0].relative_to(self.output_dir).as_posix(),
+                        f"cat-{i % 10}",
+                        "2026-10-27T00:00:00+00:00",
+                    )
+                    for i in range(1, files, 25)[:2_000]
+                ],
+            )
         return listed
 
     _BUDGET_REQUESTS = (