Remove redundant ui/.gitignore

Vite scaffolding, unmodified since the UI was added. Everything in it that this
project produces is already covered by the root .gitignore.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

ui/.gitignore

@@ -1,24 +0,0 @@
-# Logs
-logs
-*.log
-npm-debug.log*
-yarn-debug.log*
-yarn-error.log*
-pnpm-debug.log*
-lerna-debug.log*
-
-node_modules
-dist
-dist-ssr
-*.local
-
-# Editor directories and files
-.vscode/*
-!.vscode/extensions.json
-.idea
-.DS_Store
-*.suo
-*.ntvs*
-*.njsproj
-*.sln
-*.sw?