test(web): cover /compact instructions in the composer dispatch plan

Takeover tests for #20236: a stale Claude session still compacts before
ordinary messages and /compactfoo, but /compact with instructions or
whitespace is the only compaction.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
111533a687Julius Marminge committed on 10/23/2026, 8:00:56 AMparent1470744
1 file changedLine totals unavailable