Add lane lifecycle requirements REQ-101 to REQ-103 (#166, #165) Adds three planned requirements under SYS-REQ-027, approved by the operator on 2026-11-09: - REQ-101 / TEST-103: each lane run uses a disposable instance of a base image whose digest matches its receipt (#166 Draft A). - REQ-102 / TEST-104: lane teardown is bound to the verified VM UUID and an allow-listed state, and reports removal only after observing absence (#166 Draft B). - REQ-103 / TEST-105: a lane guest has no GitHub Actions runner configured or registered, checked at packaging and clone time (#165 Draft C). IDs follow approval order. Updates the SRS, RTM, planned test-case hubs, and SYS-REQ-027 traceability. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>