* fix(auth): allow invited org members to start workflow runs
Users invited to an org could not start workflows belonging to that org
because the authorization check compared actor.selected_organization_id
directly against workflow.organization_id. An invited user's selected
org correctly reflects the invited org, but if the Stack Auth token
resolves to a different org id than expected the strict equality fails.
Per api/AGENTS.md: "Whenever you read or write an organization-scoped
field, you must filter or validate by organization_id." The correct
policy is org membership, not selected-org identity.
- Add is_user_member_of_organization() to OrganizationClient; queries
the organization_users association table directly (no lazy-load risk).
- Replace the identity check in authorize_workflow_run_start() with a
membership lookup. Deny when actor_user.id is not in the org's member
set; error_code stays workflow_not_found to avoid leaking existence.
- Update test: rename rejects_actor_from_another_org to
rejects_actor_not_a_member (reflects actual policy), add positive test
allows_invited_member that seeds membership and asserts has_quota=True.
Closes#491
* fix(auth): skip membership check for personal workflows (organization_id=None)
When workflow.organization_id is None (personal or legacy workflow with no
org), the membership lookup was still called, producing a SQL IS NULL
comparison that matched nothing and denied the run.
Guard the check so it only runs when the workflow is org-scoped.
Adds a regression test confirming that an actor with a known id can start a
personal workflow without triggering is_user_member_of_organization.
* fix(auth): fail closed on workflow membership lookup errors
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Co-authored-by: Abhishek Kumar <abhishek@a6k.me>
