fix: add missing Credentials import and host-scoped credential check

- Import Credentials type from backend.data.model
- Add host-scoped credential matching to find_matching_credential
  (consistent with match_user_credentials_to_graph)

autogpt_platform/backend/backend/api/features/chat/tools/utils.py

@@ -8,6 +8,7 @@ from backend.api.features.library import model as library_model
 from backend.api.features.store import db as store_db
 from backend.data.graph import GraphModel
 from backend.data.model import (
+    Credentials,
     CredentialsFieldInfo,
     CredentialsMetaInput,
     HostScopedCredentials,
@@ -288,13 +289,15 @@ def find_matching_credential(
     available_creds: list[Credentials],
     field_info: CredentialsFieldInfo,
 ) -> Credentials | None:
-    """Find a credential that matches the required provider, type, and scopes."""
+    """Find a credential that matches the required provider, type, scopes, and host."""
     for cred in available_creds:
         if cred.provider not in field_info.provider:
             continue
         if cred.type not in field_info.supported_types:
             continue
-        if not _credential_has_required_scopes(cred, field_info):
+        if cred.type == "oauth2" and not _credential_has_required_scopes(cred, field_info):
+            continue
+        if cred.type == "host_scoped" and not _credential_is_for_host(cred, field_info):
             continue
         return cred
     return None