feat: barebones MVP — editor, live LSP, and preview

Backend (typst-leaf-backend)
- REST API for multi-project file management under PROJECTS_ROOT
  (list/create projects, get file tree, read/write files; zod-validated
  sandbox prevents path traversal).
- LSP thin proxy: spawns a single tinymist lsp process, pipes one active
  WebSocket straight to its stdio via vscode-ws-jsonrpc. New connections
  trigger a takeover (old session disposed, fresh tinymist spawned).
- Live preview pipeline: the frontend sends tinymist.startDefaultPreview
  over the LSP wire, reads the returned data-plane port, and relays it to
  the backend. The backend proxies /preview (WS, with retry and an Origin
  header for typst-preview) and /preview-app (HTTP, injecting a script that
  rewrites the webview's WS path to /preview and forces light mode).
- Graceful SIGTERM/SIGINT shutdown.
- Auto-seeds a hello project on first boot.
- Removed execa dependency (no longer needed).

Frontend (typst-leaf-frontend)
- Monaco editor with typst syntax highlighting (Monarch tokenizer) and
  live LSP diagnostics (markers), completion, hover, definitions, and
  formatting — all driven by a raw JSON-RPC WebSocket client (no
  monaco-languageclient or vscode-api dependency).
- Project picker and file tree sidebar.
- Live preview pane: iframes the typst-preview webview through the
  backend's /preview-app proxy, so the pipedepeline works remotely.
- Monaco bundled locally (no CDN) with a Vite worker setup.
- Vite dev proxy so relative /api, /lsp, /preview, and /preVIEW-app URLs
  reach the backend on port 4000.
- Light-mode UI (editor 'vs' theme, white chrome).
- Prevent esbuild from tree-shaking monaco.editor services
  (optimizeDeps.esbuildOptions.treeShaking: false).

Infrastructure
- Added vscode-ws-jsonrpc to backend dependencies.
- Removed monaco-languageclient and vscode-ws-jsonrpc from frontend
  dependencies (replaced by the raw JSON-RPC client).
- Added monaco-editor as a direct frontend dependency.
- Updated README (correct frontend port 1420, tinymist install command,
  environment variables, architecture).
- Added projects/ to .gitignore.
- Renamed Tauri productName and page title to typst-leaf.

README.md

@@ -4,55 +4,64 @@ A completely self-hostable, high-performance editor for [Typst](https://typst.ap
 
 **Features:**
 * **Instant Preview:** Sub-50ms incremental compilation using `tinymist`.
-* **Vim Mode:** First-class support via Monaco.
-* **Git Native:** No hidden databases. Your projects are just folders with `.git`.
-* **Hybrid:** Run it in Docker on your server, or as a native desktop app via Tauri.
+* **Live diagnostics & autocomplete** from the Typst language server.
+* **Git Native:** No hidden databases. Your projects are just folders.
+* **Hybrid:** Run it in a browser, or as a native desktop app via Tauri.
 
 ## 📂 Repository Structure
 
 ```text
 typst-leaf/
-├── typst-leaf-backend/     # Node.js/TS server (manages tinymist & git)
+├── typst-leaf-backend/     # Node.js/TS server (spawns tinymist, REST + WS)
 ├── typst-leaf-frontend/    # React + Monaco frontend (includes Tauri)
 ├── VISION.md               # Project philosophy and architecture
 └── AGENTS.md               # Guidelines for AI coding assistants
-
 ```
 
+## Prerequisites
+
+* **Node.js 20+**
+* **pnpm** (10+)
+* **Rust** (only required for the Tauri desktop wrapper)
+* **`tinymist`** on your `PATH` — the Typst language server & preview engine:
+  ```bash
+  cargo install --git https://github.com/Myriad-Dreamin/tinymist --bin tinymist --locked tinymist-cli
+  ```
+
 ## 🚀 Quick Start (Development)
 
-**Prerequisites:**
-
-* Node.js 20+
-* pnpm
-* Rust (for Tauri)
-* `tinymist` binary installed in your PATH.
-
 ```bash
-# 1. Install dependencies
+# 1. Install workspace dependencies
 pnpm install
 
-# 2. Start the backend (Port 4000)
-cd typst-leaf-backend
-pnpm dev
+# 2. Start the backend (port 4000)
+pnpm --filter typst-leaf-backend dev
 
-# 3. Start the web frontend (Port 3000)
-# (In a new terminal)
-cd typst-leaf-frontend
-pnpm dev
-
-# 4. Start Tauri Desktop App (Optional)
-# (In a new terminal)
-cd typst-leaf-frontend
-pnpm tauri dev
+# 3. Start the web frontend (port 1420 — mandated by Tauri)
+pnpm --filter typst-leaf-frontend dev
 
+# 4. (Optional) Launch the Tauri desktop wrapper
+pnpm --filter typst-leaf-frontend tauri dev
 ```
 
+Then open <http://localhost:1420> in your browser. A `hello` project is auto-seeded on first run.
+
+### Environment variables
+
+| Var | Default | Description |
+| --- | --- | --- |
+| `PROJECTS_ROOT` | `<repo>/projects` | Directory under which project folders live. The backend refuses to read or write outside this root. |
+| `TINYMIST_PREVIEW_HOST` | `127.0.0.1` | Host the tinymist preview server binds to. |
+| `TINYMIST_PREVIEW_PORT` | `23635` | Port the tinymist preview server binds to. |
+| `PORT` (backend) | `4000` | Backend HTTP/WS port. |
+| `FRONTEND_ORIGIN` (backend) | `http://localhost:1420` | CORS origin allowed to call the REST API. |
+
 ## 🏗️ Architecture
 
 * **Editor:** Monaco Editor
-* **LSP:** `tinymist` (via WebSocket proxy)
-* **Communication:**
-    * `ws://localhost:4000/lsp` -> Tinymist Language Server
-    * `ws://localhost:4000/preview` -> Tinymist Preview Service
+* **LSP:** `tinymist` over a WebSocket thin proxy
+* **Preview:** Backend spawns `tinymist preview <file>` on demand; the frontend iframes its webview for live SVG updates.
+* **Data plane:**
+    * `ws://localhost:4000/lsp` → `tinymist lsp` (single active connection, takeover on reconnect)
+    * `GET /api/projects`, `GET/PUT /api/projects/:p/file?path=…`, `POST /api/projects/:p/focus?path=…`