The raw-output watcher modes (all/result/error) and the interim running
update sent the bracketed debug wrapper with the internal process id
(`[Background process proc_… finished with exit code N~ Here's the final
output: …]`) to Telegram/Discord/Slack chats. Reuse the concise one-line
status header for every mode and append the bounded, ANSI-stripped output
tail in a code block; the running update gets the same shape.
Salvaged from #54266 (rebased onto the post-#102117 run_notifications
sibling; the concise mode had landed in between, so the header is shared
rather than reimplemented). Also covers #13122 (ANSI stripping).
Tim Smykov
bfbf31d576