ui: Help › Crash Reports lists the saved reports to report, copy or delete (#300)

diagnostics.crash_reports.delete deletes one report or all. The window lists each report
(when, what, how many times) with Report…, Copy Path and Delete, and Delete All; ui.prompt
answers it over the control channel.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

crates/engine/src/cmd/mod.rs

@@ -165,6 +165,7 @@ pub static ALL: &[CommandSpec] = &[
     results::CLEAR,
     diagnostics::CRASH_REPORTS,
     diagnostics::CRASH_REPORT,
+    diagnostics::CRASH_REPORTS_DELETE,
     diagnostics::BUG_REPORT,
     diagnostics::CRASH_TEST,
     update::CHECK,