feat(fc3b): /api/platforms blueprint (read-only registry view)

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

tests/test_api_platforms.py

@@ -0,0 +1,53 @@
+import re
+
+import pytest
+
+from backend.app import create_app
+
+pytestmark = pytest.mark.integration
+
+
+@pytest.fixture
+async def app():
+    return create_app()
+
+
+@pytest.fixture
+async def client(app):
+    async with app.test_client() as c:
+        yield c
+
+
+@pytest.mark.asyncio
+async def test_platforms_returns_gs_six(client):
+    resp = await client.get("/api/platforms")
+    assert resp.status_code == 200
+    body = await resp.get_json()
+    platforms = body["platforms"]
+    assert set(platforms.keys()) == {
+        "patreon", "subscribestar", "hentaifoundry",
+        "discord", "pixiv", "deviantart",
+    }
+    assert "fanbox" not in platforms
+
+
+@pytest.mark.asyncio
+async def test_platforms_record_shape(client):
+    body = await (await client.get("/api/platforms")).get_json()
+    patreon = body["platforms"]["patreon"]
+    for key in (
+        "key", "name", "description", "auth_type", "requires_auth",
+        "url_pattern", "url_examples", "default_config", "notes",
+    ):
+        assert key in patreon
+    assert patreon["auth_type"] == "cookies"
+    re.compile(patreon["url_pattern"])
+    assert patreon["default_config"]["sleep"] == 3.0
+
+
+@pytest.mark.asyncio
+async def test_platform_auth_types_match_gs(client):
+    body = await (await client.get("/api/platforms")).get_json()
+    assert body["platforms"]["discord"]["auth_type"] == "token"
+    assert body["platforms"]["pixiv"]["auth_type"] == "token"
+    assert body["platforms"]["patreon"]["auth_type"] == "cookies"