Closes#1847.
The splash is the only surface with a Show/Copy affordance for these lines, and
it unmounts the moment the stage flips to ready — so on a successful first run
the whole install log was gone for good, with no completion pause and nowhere
to retrieve it. A user who wanted to check what had just been installed, or
attach it to a bug report, had nothing.
The lines are written to bootstrap.log beside backend.log now, so everything
about a run is in one directory and a bug report does not have to hunt in two.
Truncated once per process rather than appended forever: a bootstrap is a
single episode and the useful question is always "what happened this time".
That also bounds the file across repeated retries without needing a hook on
every restart path. The docs say so, and say to copy it first if you need a
superseded attempt.
Best effort throughout — a log that cannot be written must never take the
bootstrap down with it, and a test pins that it does not.
The counter half of this issue (Activity frozen at 200) was already fixed on
main by #1918; I verified that before starting rather than assuming the whole
issue was open.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017ypcgSsh5j2PEonSJiAU1S
