feat(v2): add xterm.js terminal pane with Canvas addon

- Install @xterm/xterm, @xterm/addon-canvas, @xterm/addon-fit, @tauri-apps/api
- TerminalPane: xterm.js with Catppuccin Mocha theme, auto-fit, resize observer
- PTY bridge: Tauri invoke wrappers + event listeners for data/exit
- Bidirectional streaming: keyboard input -> PTY write, PTY output -> xterm write
- 100ms debounced resize propagation to PTY backend

v2/package.json

@@ -20,5 +20,11 @@
     "svelte-check": "^4.3.4",
     "typescript": "~5.9.3",
     "vite": "^7.3.1"
+  },
+  "dependencies": {
+    "@tauri-apps/api": "^2.10.1",
+    "@xterm/addon-canvas": "^0.7.0",
+    "@xterm/addon-fit": "^0.11.0",
+    "@xterm/xterm": "^6.0.0"
   }
 }