feat(ui,infra): SvelteKit ui scaffold, Makefile, pre-commit, claude hooks

ui/: SvelteKit 2 + Svelte 5 + Tailwind 4 + shadcn-svelte (luma, lucide)
on bun with ultracite; adapter-static with SPA fallback; theme tokens
taken from msos. Dockerfile gains a bun stage that builds ui/build.
Makefile and pre-commit cover ruff, ty, ultracite and svelte-check;
.claude settings run the matching fixer after edits. docs/PRODUCT.md
captures product truth for the UI work.

ui/README.md

@@ -0,0 +1,42 @@
+# sv
+
+Everything you need to build a Svelte project, powered by [`sv`](https://github.com/sveltejs/cli).
+
+## Creating a project
+
+If you're seeing this, you've probably already done this step. Congrats!
+
+```sh
+# create a new project
+npx sv create my-app
+```
+
+To recreate this project with the same configuration:
+
+```sh
+# recreate this project
+bun x sv@0.17.0 create --template minimal --types ts --install bun ui
+```
+
+## Developing
+
+Once you've created a project and installed dependencies with `npm install` (or `pnpm install` or `yarn`), start a development server:
+
+```sh
+npm run dev
+
+# or start the server and open the app in a new browser tab
+npm run dev -- --open
+```
+
+## Building
+
+To create a production version of your app:
+
+```sh
+npm run build
+```
+
+You can preview the production build with `npm run preview`.
+
+> To deploy your app, you may need to install an [adapter](https://svelte.dev/docs/kit/adapters) for your target environment.