Close lmux M3/M4 acceptance and final review

[zhnt]

Objective

Close the remaining lmux M3/M4 acceptance gates for the managed Linux workspace service already merged through PRs #601 and #602.

Scope

• reproduce and resolve the managed-product-history-restore startup failure without relaxing lifecycle or evidence checks;
• run a fresh uninterrupted formal A/A campaign for managed-product-first-use under the accepted ARD-004 comparison contract;
• confirm the retained managed-mux and long-history warm evidence by read-only source-bound reevaluation;
• run the documented installed, disconnect/reconnect, exact-stop, cleanup, and performance gates;
• perform final architecture, lifecycle/security, and Product/test review of the delivered goal;
• update lmux status documents to distinguish accepted evidence from diagnostic-only records.

Non-goals

• no new lmux capability or protocol;
• no threshold relaxation, sample filtering, or report rewriting;
• no remote/SSH feature expansion beyond the documented local PTY acceptance scope;
• no unrelated PLC or TUI redesign.

Exit criteria

• every required formal campaign is complete, valid, source-bound, and settled, or the contract records an independently reviewed product defect with a narrow fix and rerun;
• required static and regression gates pass;
• no unresolved P0/P1/P2 finding remains in the final three-perspective review;
• the architecture status accurately states what is and is not accepted.