fix(runner): batch auto-install to prevent race conditions and silent UI

- Auto-install now batches all registrations into a single deferred
  install call (200ms debounce), preventing race conditions where
  multiple deferred installs would reject each other
- Silent auto-install no longer pops open the Glaze UI window
- runner.install() accepts { silent: true } option to suppress UI
  and notifications
- Add CI workflow (stylua format check + luacheck lint)
- Add .stylua.toml and .luacheckrc configs
- Fix empty if branch lint warning in runner.lua
- Apply stylua formatting to checker.lua and health.lua

.github/workflows/ci.yml

@@ -0,0 +1,25 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Check formatting with StyLua
+        uses: JohnnyMorganz/stylua-action@v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          version: latest
+          args: --check .
+
+      - name: Lint with luacheck
+        uses: lunarmodules/luacheck@v1
+        with:
+          args: lua/