feat(provider): support Codex subscriptions with ChatGPT sign-in (#2513)

* feat(provider): support Codex subscriptions with ChatGPT sign-in

* style: format Codex live integration test

* fix(provider): preserve Codex identity in temporary model tests

* fix(web): portal provider selector without dialog overflow

* fix(web): allow native scrolling in provider dropdown

* fix(provider): surface safe Codex quota and upstream errors

* fix(web): provide reliable Codex copy feedback in dialogs

* feat(provider): confirm cascade deletion from edit dialog

* fix(persistence): discard connections after failed commit

* fix(web): polish provider loading and confirmation motion

---------

Co-authored-by: dadachann <185672915+dadachann@users.noreply.github.com>

src/langbot/pkg/entity/persistence/model.py

@@ -33,6 +33,28 @@ class ModelProvider(Base):
     )
 
 
+class CodexCredential(Base):
+    """Server-only OAuth state. Never joined into provider/model serialization."""
+
+    __tablename__ = 'codex_credentials'
+
+    provider_uuid = sqlalchemy.Column(sqlalchemy.String(255), primary_key=True)
+    workspace_uuid = sqlalchemy.Column(sqlalchemy.String(36), nullable=False)
+    payload = sqlalchemy.Column(sqlalchemy.JSON, nullable=False, default=dict)
+    version = sqlalchemy.Column(sqlalchemy.Integer, nullable=False, default=0)
+    lease_owner = sqlalchemy.Column(sqlalchemy.String(64), nullable=True)
+    lease_until = sqlalchemy.Column(sqlalchemy.Float, nullable=False, default=0)
+    __table_args__ = (
+        sqlalchemy.ForeignKeyConstraint(
+            ['workspace_uuid', 'provider_uuid'],
+            ['model_providers.workspace_uuid', 'model_providers.uuid'],
+            name='fk_codex_credentials_workspace_provider',
+            ondelete='CASCADE',
+        ),
+        sqlalchemy.Index('ix_codex_credentials_workspace', 'workspace_uuid'),
+    )
+
+
 class LLMModel(Base):
     """LLM model"""