Add a Restart specific permission for RestartStack

[AzScep]

Problem

RestartStack, StartStack, StopStack, DeployStack and DestroyStack all require the Execute level.
There is no way to let a user (or a service user driving an automation) restart a stack without also letting it stop, destroy, or redeploy that stack.
A leaked restart-only credential should not be able to take an app down.

Change

• Add SpecificPermission::Restart.
  A user with Read and Restart on a Stack can run RestartStack, including for single services.
  Every other stack execution still requires Execute, and UpdateStack still requires Write.
  Like the other specific permissions, Restart given on a Server is inherited by that server's Stacks.
• Add get_check_any_permissions (and setup_stack_execution_any), which pass when the user fulfils any one of several permission sets.
  get_check_permissions now delegates to it with a single set, and its error message is unchanged.
• ExecuteCompose gains allowed_permissions(), defaulting to Execute; RestartStack returns [Execute, Read + Restart].
• Offer Restart for Stacks in the UI's specific permission selector, regenerate the TS types, and document it in permissioning.md.

Users without Restart see no behaviour change.
The UI still shows stack executions only with Execute, so a restart-only user restarts through the API; happy to follow up with a UI change if you want one.

Verification

• 4 unit tests in permission::tests in Core and 2 in the client's entities::permission (serde round trip and unchanged variant names).
  Removing Read + Restart from RestartStack::allowed_permissions makes 2 of the Core tests fail.
• cargo fmt --check and clippy clean for the changed files.
• End to end on a local Mongo + Core + Periphery (outbound) setup with this Core build:
  • a service user with Read + [Logs, Restart] on a stack restarts it and reads its logs;
  • the same user is refused DeployStack, StopStack, DestroyStack, StartStack, PauseStack, PullStack (the Update completes unsuccessfully with the permission error) and UpdateStack;
  • a user with Read + [Logs] is still refused RestartStack, a user with Execute still restarts, and Restart without Read is refused.
    On upstream 2.3.3 the same script fails at granting Restart (unknown variant).

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