REQ-107, TEST-109: lane guest access channel; cite B2 (PR #213) New REQ-107 (reach a lane guest only through its run's key-bound channel) and TEST-109, linked from the SRS, RTM, planned test cases and SYS-REQ-027. REQ-091, REQ-093 and REQ-106 cite the workload placement code. Status stays Planned: offline tests pass, no live proof yet. REQ-104 and TEST-106 remain reserved for #181. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>