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.

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

ui/src/app.d.ts

@@ -0,0 +1,13 @@
+// See https://svelte.dev/docs/kit/types#app.d.ts
+// for information about these interfaces
+declare global {
+  namespace App {
+    // interface Error {}
+    // interface Locals {}
+    // interface PageData {}
+    // interface PageState {}
+    // interface Platform {}
+  }
+}
+
+export {};