chore: Replace Prettier with oxfmt and ESLint with oxlint (#119)

pnpm lint runs oxlint and pnpm format runs oxfmt: lint ~0.3s instead of ~20s, format check ~0.2s instead of ~11s, with far less memory. Configs come from the official migration tools (.oxlintrc.json from eslint.config.js, .oxfmtrc.json from the Prettier config); six new findings fixed or suppressed in 4 files. No code is reformatted.

Claude-Session: https://claude.ai/code/session_01VUYsdXA2nkF5v6zsC93dpn
Co-authored-by: jaw52 <[email protected]>

src/features/debugger/editor/breakpointGutter.ts

@@ -141,7 +141,7 @@ export function breakpointGutter(ctx: EditorDocContext): Extension {
       // IDEA tints the whole line of an active breakpoint.
       EditorView.decorations.from(f, (markers) => {
         const lines: Array<ReturnType<Decoration["range"]>> = [];
-        for (let it = markers.iter(); it.value; it.next())
+        for (const it = markers.iter(); it.value; it.next())
           if (!DISABLED_LOOKS.has(it.value.look)) lines.push(bpLine.range(it.from));
         return Decoration.set(lines);
       }),