chore(ui): refactor workspace to monorepo (#70)

## Summary by Sourcery

Refactor the UI project structure into a pnpm monorepo packages layout
and align tooling and automation with the new paths.

Enhancements:
- Reorganize the UI app from the root ui directory into packages/ui
within a pnpm workspace.
- Update pnpm workspace configuration to include all packages under
packages/*.
- Adjust paths in changeset configuration so the @dropout/ui package
resolves from packages/ui.

Build:
- Update pre-commit configuration paths and arguments to reflect the new
UI location and normalize hook argument formatting.
- Update Dependabot configuration so npm updates target /packages/ui
instead of /ui.

CI:
- Update GitHub Actions workflows to watch packages/** instead of ui/**
and to run frontend tasks from packages/ui.
- Update pnpm cache dependency paths in workflows to use the root
pnpm-lock.yaml.
- Simplify frontend install steps in test workflows to run from the
repository root.

Chores:
- Add a new index.html under packages/ui and remove the old
ui/index.html to match the new project layout.

1 files changed, 22 insertions, 0 deletions

diff --git a/packages/ui/tsconfig.app.json b/packages/ui/tsconfig.app.json
new file mode 100644
index 0000000..addb46d
--- /dev/null
+++ b/packages/ui/tsconfig.app.json
@@ -0,0 +1,22 @@
+{
+  "extends": "@tsconfig/svelte/tsconfig.json",
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.app.tsbuildinfo",
+    "target": "ES2022",
+    "useDefineForClassFields": true,
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "types": ["svelte", "vite/client"],
+    "noEmit": true,
+    /**
+     * Typecheck JS in `.svelte` and `.js` files by default.
+     * Disable checkJs if you'd like to use dynamic types in JS.
+     * Note that setting allowJs false does not prevent the use
+     * of JS in `.svelte` files.
+     */
+    "allowJs": true,
+    "checkJs": true,
+    "moduleDetection": "force"
+  },
+  "include": ["src/**/*.ts", "src/**/*.js", "src/**/*.svelte"]
+}