feat(artist): resolve patreon + subscribestar display names at add-time (#130 step 5)

Parity with pixiv (operator ask): the extension add now resolves the real
display name for our other native platforms too, not just the URL handle.
patreon_resolver.resolve_display_name reads the campaigns API's
attributes.name; SubscribeStarClient.resolve_display_name pulls the creator
name off the profile page (og:title, else the <title> stripped of the
SubscribeStar suffix). extension_service._resolve_artist_name dispatches per
platform (pixiv=token, patreon/subscribestar=cookies via get_cookies_path),
best-effort in an executor, falling back to the readable URL handle on any
failure. Still all curator core — the extension is unchanged (sends only the
URL). gallery-dl platforms keep the handle (readable, no native client).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CDgx8bQS5YrGRK76v8HUnM

tests/test_api_extension.py

@@ -85,25 +85,42 @@ async def test_quick_add_reuses_source_artist_after_rename(client, ext_key):
 
 
 @pytest.mark.asyncio
-async def test_resolve_artist_name_pixiv_uses_api(db, monkeypatch):
-    # #130: a pixiv add resolves the display name via the app API (with a token),
-    # not the numeric id; falls back to the id without crypto/token.
+async def test_resolve_artist_name_dispatches_per_platform(db, monkeypatch):
+    # #130: each native platform resolves its real display name at add-time
+    # (pixiv=token API, patreon=campaigns API, subscribestar=profile page);
+    # gallery-dl platforms and any failure fall back to the URL handle.
+    from backend.app.services import patreon_resolver
     from backend.app.services.credential_service import CredentialService
     from backend.app.services.extension_service import ExtensionService
     from backend.app.services.pixiv_client import PixivClient
+    from backend.app.services.subscribestar_client import SubscribeStarClient
 
     async def _tok(self, platform):
-        return "tok" if platform == "pixiv" else None
-    monkeypatch.setattr(CredentialService, "get_token", _tok)
-    monkeypatch.setattr(
-        PixivClient, "resolve_display_name", lambda self, uid: "Kurotsuchi Machi"
-    )
+        return "tok"
 
-    svc = ExtensionService(db, crypto=object())     # crypto unused (token stubbed)
-    assert await svc._resolve_artist_name("pixiv", "555") == "Kurotsuchi Machi"
-    assert await svc._resolve_artist_name("patreon", "alice") == "alice"   # passthrough
-    # No crypto → no resolution attempt → fall back to the raw handle.
-    assert await ExtensionService(db)._resolve_artist_name("pixiv", "555") == "555"
+    async def _cookies(self, platform):
+        return "/tmp/cookies.txt"
+
+    monkeypatch.setattr(CredentialService, "get_token", _tok)
+    monkeypatch.setattr(CredentialService, "get_cookies_path", _cookies)
+    monkeypatch.setattr(PixivClient, "resolve_display_name", lambda self, uid: "Pixiv Name")
+    monkeypatch.setattr(patreon_resolver, "resolve_display_name", lambda v, c: "Patreon Name")
+    monkeypatch.setattr(SubscribeStarClient, "resolve_display_name", lambda self, u: "SS Name")
+
+    svc = ExtensionService(db, crypto=object())     # crypto seam only (calls stubbed)
+    assert await svc._resolve_artist_name(
+        "pixiv", "555", "https://www.pixiv.net/users/555") == "Pixiv Name"
+    assert await svc._resolve_artist_name(
+        "patreon", "maewix", "https://patreon.com/maewix") == "Patreon Name"
+    assert await svc._resolve_artist_name(
+        "subscribestar", "sabu", "https://subscribestar.adult/sabu") == "SS Name"
+    # gallery-dl platform → readable handle passthrough (no resolver).
+    assert await svc._resolve_artist_name("hentaifoundry", "Foo", "u") == "Foo"
+    # No crypto → no resolution attempt → the raw handle.
+    assert await ExtensionService(db)._resolve_artist_name("pixiv", "555", "u") == "555"
+    # Resolver returns None → fall back to the handle.
+    monkeypatch.setattr(patreon_resolver, "resolve_display_name", lambda v, c: None)
+    assert await svc._resolve_artist_name("patreon", "maewix", "u") == "maewix"
 
 
 @pytest.mark.parametrize("url,platform,slug", [