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/tsconfig.json

@@ -0,0 +1,20 @@
+{
+  "extends": "./.svelte-kit/tsconfig.json",
+  "compilerOptions": {
+    "rewriteRelativeImportExtensions": true,
+    "allowJs": true,
+    "checkJs": true,
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "skipLibCheck": true,
+    "sourceMap": true,
+    "strict": true,
+    "moduleResolution": "bundler"
+  }
+  // Path aliases are handled by https://svelte.dev/docs/kit/configuration#alias
+  // except $lib which is handled by https://svelte.dev/docs/kit/configuration#files
+  //
+  // To make changes to top-level options such as include and exclude, we recommend extending
+  // the generated config; see https://svelte.dev/docs/kit/configuration#typescript
+}