180ba03bfd
Fixes #4388. Refs #4027. Observe cancellation during first-window waits and state reads; preserve cancellation and caller reasons before cleanup and retain partial observations when cleanup fails. Keep late cancellation and cleanup failure precedence. Validation: 49 focused cases, static/docs checks, six controlled verifier-oracle cases and 39 current-head CI checks passed. Codex and Greptile found no remaining blocking issues. Real Joplin cancellation phases verified; complete Linux cleanup/first-signal CLI exit and packaged-runtime startup remain explicitly unverified/failed. Both verifiers now fail incomplete cleanup, including after main-process exit. Co-authored-by: gensokyo-dev <342580529+gensokyo-dev@users.noreply.github.com> Co-authored-by: Kaoru0822 <208281322+kaoru0822-kitauji@users.noreply.github.com> Co-authored-by: Adolanium <94890352+Adolanium@users.noreply.github.com>