Send-test uses form auth values directly (no save required)

The "send test" button now passes the currently typed token / login /
password to /api/test, falling back to saved defaults. Previously the
test only used saved settings, so testing before clicking Save sent no
auth and failed with 403 on access-controlled ntfy servers.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/schemas.py

@@ -78,6 +78,10 @@ class SettingsIn(BaseModel):
 class TestIn(BaseModel):
     server: str = ""
     topic: str
+    # Optional auth from the form; falls back to saved default-server creds.
+    token: str | None = None
+    username: str | None = None
+    password: str | None = None
 
 
 class PreviewIn(BaseModel):