[StudentWeis]

Summary

Preserve newer shortcut drafts when asynchronous registration finishes, reject unsupported file URI authorities, and capture update-helper failures on stderr. History rows now borrow records and prepare bounded previews only when needed.

Linked Issue

Closes #304

Changes

• Preserve edits made during hotkey registration, retain the submission guard across window recreation, and release it even if completion arrives while the window is closed.
• Parse file URI authorities exactly: accept empty authority or case-insensitive localhost, reject unsupported hosts and incomplete URIs, and preserve literal filesystem whitespace and percent characters.
• Install a scoped stderr tracing subscriber around startup/update handling so rollback failures reach the helper log before normal application logging starts.
• Borrow history records instead of cloning entire records, remove redundant preview copies, and retain Unicode-safe bounded text for requested previews.
• Add regressions for hotkey window lifecycle, unsupported URI authorities, million-character Unicode previews, payload presentation and update-helper rollback diagnostics. The stale-installation fixture recompiles a valid replacement executable with a different optimization level.

Testing

• scripts/precheck.sh --check passes locally: 794 Rust tests passed, 3 existing tests ignored; 83 Python tests passed; Clippy, formatting, resource checks, core dependency boundaries, private D-Bus tray test and rustdoc passed.
• New / updated tests cover the change. Regression probes failed against the original implementation before the fixes.
• All three update handoff scenarios pass: healthy startup, failed startup rollback and stale installation recovery with stderr diagnostics.

Validation ran on Linux using headless GPUI and native helper subprocesses. Native macOS, Windows and Wayland desktop end-to-end tests were not run.

Self-Check

• PR title follows Conventional Commits
• No hardcoded user-facing strings — no new display strings or locale keys
• Errors defined with thiserror (no manual impl Display/Error) — no new error types
• No unrelated changes mixed in