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/hooks/useInstallPlugin.ts

@@ -1,9 +1,9 @@
-import { installPluginFromDirectory } from '@yaakapp-internal/plugins';
-import { useFastMutation } from './useFastMutation';
+import { installPluginFromDirectory } from "@yaakapp-internal/plugins";
+import { useFastMutation } from "./useFastMutation";
 
 export function useInstallPlugin() {
   return useFastMutation<void, unknown, string>({
-    mutationKey: ['install_plugin'],
+    mutationKey: ["install_plugin"],
     mutationFn: async (directory: string) => {
       await installPluginFromDirectory(directory);
     },