Provision labels correctly in the recommended Squad activation fast path #1959

Parent: #1957

Blocked by: temporary-ID targeting work under this epic.

Problem

The recommended /squad activate command can follow a fast path that still relies on labels supplied directly to create_issue. On a fresh repository, missing Squad labels may therefore remain unprovisioned even after the full plan activate path is corrected.

Scope

Apply the verified temporary-ID and safe-output label-provisioning pattern to the /squad activate fast path.

Success criteria

• A fresh repository with no Squad labels can use /squad activate without manual label setup.
• Every newly created fast-path item uses a unique gh-aw temporary ID shared by its create_issue and add_labels operations.
• Existing/reused issues use verified real issue numbers.
• Every activated issue receives squad; certified single-owner items receive exactly the correct squad:{agent} label.
• @copilot, multi-owner, and non-roster behavior matches the full activation path.
• The triggering intent issue receives no accidental owner label.
• Reruns remain idempotent.
• Tests demonstrate parity between both activation paths and strict gh-aw compilation passes.

Out of scope

Activation-result reporting, operation-capacity policy, checker distribution, and E4 execution.