* fix(suggest-compact): clean up old counter temp files
claude-tool-count-<sessionId> files were written into the OS temp dir
on every hook run and never removed, accumulating one orphan per
session indefinitely.
Sweep stale counter files at the top of main() before opening the
active counter. Retention is env-tunable via COMPACT_STATE_TTL_DAYS
(default 14 days); invalid values fall back to the default. The
active session's counter file is preserved unconditionally even if
its mtime is past the cutoff. Failures during the sweep are swallowed
to preserve the always-exit-0 hook contract.
Adds 7 regression tests covering the sweep, env-var validation, and
the always-exit-0 invariant under a populated temp dir.
Fixes#2156
* fix(suggest-compact): preserve counter files at the TTL cutoff boundary
The cleanup sweep used `mtimeMs > cutoffMs` to short-circuit, which
matched files whose mtime sits exactly on the cutoff boundary and
deleted them. The cleanupOldCounters docstring promises only files
*older than* retentionDays are removed; a file at age == retentionDays
is not older than retentionDays, so it must survive.
Switch the comparison to `>=` so only strictly older files fall
through to deletion. Add a regression test that pins boundary-aged
files (mtimeMs sitting just past the projected cutoff) are preserved.
Refs #2156
a08445ad78