Record what landed for recv_match/try_recv_match and update the
no-select gotcha: selective receive stayed per-channel rather than
introducing a cross-channel mailbox.
- task.md: mark roadmap #3 done (record the resolved dedicated-inbox
decision + test list), add the feature commit to the resume block, note
the now-resolved trap_exit channel question, and list spawn_link under #5.
- supervisor.rs: the module comment predated cancellation; rewrite it to say
sibling/link/shutdown stops are cooperative (request_stop), not that
one_for_all / rest_for_one / links are impossible.
- README: add monitor + link rows, refresh the supervisor row and src layout,
and drop restart-intensity caps from "what's not here" (shipped in #2).
Capture the handoff roadmap in-repo, with #1 and #2 marked complete
(commit SHAs, decisions taken, and the orphaned-timer bug fixed in
e80334b). #3 (links + trap_exit) flagged as next.
smarm-dev