Agent Skills: lisa-github-build-intake

GitHub counterpart to lisa-jira-build-intake. Scans a GitHub repository for issues carrying the configured `ready` build label, processes the first eligible issue, runs leaf work via the github-agent workflow in-session (culminating in lisa-implement), relabels to the configured `done` label on completion, then exits. Enforces the claim-time arm of the `leaf-only-lifecycle` rule: a parent/container with open child work (or a childless Epic) that still carries a stale build-ready label is moved out of the ready pickup queue into the configured `claimed` label with a lifecycle-repair comment, never dispatched to the build lifecycle. The `ready` label is the human-flipped signal that an issue is truly ready for direct development pickup — mirroring how Notion PRDs work product Draft → Ready → (us) In Review → Blocked|Ticketed.