Run oxfmt across repo, add format script and ignore config

Format all non-generated files with oxfmt via `vp fmt`. Add
.oxfmtignore to skip bindings/ and wasm-pack output. Add npm
format script and update DEVELOPMENT.md docs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src-web/lib/reveal.ts

@@ -1,9 +1,9 @@
-import { type } from '@tauri-apps/plugin-os';
+import { type } from "@tauri-apps/plugin-os";
 
 const os = type();
 export const revealInFinderText =
-  os === 'macos'
-    ? 'Reveal in Finder'
-    : os === 'windows'
-      ? 'Show in Explorer'
-      : 'Show in File Manager';
+  os === "macos"
+    ? "Reveal in Finder"
+    : os === "windows"
+      ? "Show in Explorer"
+      : "Show in File Manager";