fix(fc3b): replace FC-3a KNOWN_PLATFORMS w/ registry; drop /api/sources/platforms

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_api_sources.py

@@ -25,14 +25,6 @@ async def artist(db):
     return a
 
 
-@pytest.mark.asyncio
-async def test_platforms_endpoint(client):
-    resp = await client.get("/api/sources/platforms")
-    assert resp.status_code == 200
-    body = await resp.get_json()
-    assert "patreon" in body["platforms"]
-
-
 @pytest.mark.asyncio
 async def test_create_list_get_delete(client, artist):
     create = await client.post("/api/sources", json={

tests/test_source_service.py

@@ -23,8 +23,12 @@ async def _artist(db, name="Alice"):
 
 
 @pytest.mark.asyncio
-async def test_known_platforms_contains_starter_set(db):
-    assert {"patreon", "fanbox", "subscribestar", "pixiv", "deviantart"} <= KNOWN_PLATFORMS
+async def test_known_platforms_is_gs_six(db):
+    assert KNOWN_PLATFORMS == frozenset({
+        "patreon", "subscribestar", "hentaifoundry",
+        "discord", "pixiv", "deviantart",
+    })
+    assert "fanbox" not in KNOWN_PLATFORMS
 
 
 @pytest.mark.asyncio