feat(environments): only the creator or an admin can destroy an API environment

[vigneshrajsb]

Description

Builds on #256 (merged).

• Who can destroy: destroying an API-created environment is now allowed only for its creator (createdByUserId) or a user with the admin role. Anyone else gets 403 forbidden_role with "Only the creator of this environment or an admin can destroy it."

• Where it's enforced: in BuildService.requestApiEnvironmentDeletion, under the row lock, so DELETE /api/v2/environments/{uuid} and the destroy_environment MCP tool share one rule. The MCP preview phase checks the same rule, so it refuses before issuing a confirmation token.

• Environments with no recorded creator can only be destroyed by an admin.

• Personal API keys act as their owner. Service keys are machine identities, so they keep their existing repository-allowlist scoping.

• Behaviour notes:

  • Admin status comes from session roles. API keys carry no roles, so an admin using a personal key can only destroy environments they created.
  • REST DELETE on environments with no recorded creator (including PR-created ones) is now admin-only.
  • A non-creator retrying a destroy on an environment that is already tearing down now gets 403 instead of 202.

Test plan

• Unit tests for the rule: creator, admin, admin with no recorded creator, the owner's personal key and a service key are allowed; another user, a non-admin with no recorded creator, and someone else's personal key are refused. Plus an MCP test that a non-creator's preview returns forbidden_role without a token. Full Jest suite, lint, and server typecheck pass.
• In a preview: user A creates an API environment; user B's DELETE and MCP destroy_environment preview both return forbidden_role; user A and an admin can destroy it.