feat: add React frontend with search and mod pages

Add apps/web (Vite + React Router + Tailwind v4 + Zustand) with a search page and a mod page that analyzes saves via @tts/extract. Document the frontend in the README and docs.

docs/architecture.md

@@ -27,6 +27,7 @@ shared types/validation package.
 
 | Package            | Role                                        | Runtime      |
 | ------------------ | ------------------------------------------- | ------------ |
+| `apps/web`         | React frontend: search + mod pages          | Browser      |
 | `apps/proxy`       | Hono HTTP server: search + fetch endpoints  | Node         |
 | `packages/tts`     | Fetch save from Steam, BSON-parse to `TTSMod` | Node       |
 | `packages/extract` | Analyze a `TTSMod`: objects, refs, assets   | Isomorphic   |
@@ -35,15 +36,19 @@ shared types/validation package.
 ## Dependency graph
 
 ```
-apps/proxy ──► packages/tts ──► packages/shared
-      │            │
-      │            └──► (fetchMod → TTSMod)
-      ▼
-packages/extract ──► packages/tts (traverseMod) ──► packages/shared (types)
+apps/web ──► apps/proxy ──► packages/tts ──► packages/shared
+      │            │            │
+      │            │            └──► (fetchMod → TTSMod)
+      │            ▼
+      └──► packages/extract ──► packages/shared (types)
 ```
 
 ### Edges
 
+- **`apps/web` → `apps/proxy`** — calls `/search`, `/items/:id`, and
+  `/items/:id/file` over HTTP.
+- **`apps/web` → `packages/extract`** — uses `flattenObjects` / `collectRefs`
+  to analyze a loaded `TTSMod` in the browser.
 - **`apps/proxy` → `packages/tts`** — calls `fetchMod` / `getFileName` to serve
   item requests.
 - **`apps/proxy` → `packages/shared`** — uses shared types and zod schemas for
@@ -90,11 +95,15 @@ packages/extract ──► packages/tts (traverseMod) ──► packages/shared
 
 - `typescript` (strict), `tsx` (dev runner), `eslint`, `prettier`.
 - `vitest` (unit tests), colocated as `*.test.ts` next to sources.
+- `vite`, `@vitejs/plugin-react`, `tailwindcss`, `@tailwindcss/vite` — frontend
+  build/dev tooling.
 - `pnpm` workspaces for package management.
 
 ## Deployment / runtime shape
 
 - The proxy runs as a single Node process via `@hono/node-server`.
+- `apps/web` is a static Vite build served separately; during development it
+  proxies `/search`, `/items`, and `/health` to the proxy.
 - `packages/extract` is published/consumed as a plain ESM module usable from a
   browser bundle or Node.
 - No shared state between requests; each request fetches fresh.