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, 0 insertions, 22 deletions

diff --git a/ui/tsconfig.app.json b/ui/tsconfig.app.json
deleted file mode 100644
index addb46d..0000000
--- a/ui/tsconfig.app.json
+++ /dev/null
@@ -1,22 +0,0 @@
-{
-  "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"]
-}