[arzafran]

The Review panel now shows diffs with Pierre by default. Anyone who prefers the old view can set app.reviewDiffRenderer to "native".

Linear: INC-392

What changed

• Pierre is the default diff renderer, and app.reviewDiffRenderer switches back to the native one (documented in docs/settings-json.md and the settings schema).
• Pierre now applies the same 400 KB per-file limit as the native view, shows placeholders for files it can't diff, and lists untracked files.
• The Pierre view stays loaded across tab switches and is hidden while its tab is hidden, so it can't take file drops meant for the pane.
• Git's quoted diff header paths are decoded, so binary files with tabs, quotes or non-ASCII bytes in their names no longer drop out of the view. A text file with a space in its name also no longer keeps a trailing tab in its path.
• The viewer bundle is regenerated on Vite 8.

Verification

• Tagged build succeeds; structural budgets and settings docs checks pass.
• New parser regression test for quoted header paths (runs in CI).
• Not yet checked by eye: placeholder labels in light, dark and Japanese, the "+" comment flow, scroll position across tab switches, drops on a pane with a hidden Review tab, and switching the renderer to native and back.