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/src/lib/components/Terminal/TerminalPane.svelte

@@ -0,0 +1,134 @@
+<script lang="ts">
+  import { onMount, onDestroy } from 'svelte';
+  import { Terminal } from '@xterm/xterm';
+  import { CanvasAddon } from '@xterm/addon-canvas';
+  import { FitAddon } from '@xterm/addon-fit';
+  import { spawnPty, writePty, resizePty, killPty, onPtyData, onPtyExit } from '../../adapters/pty-bridge';
+  import type { UnlistenFn } from '@tauri-apps/api/event';
+  import '@xterm/xterm/css/xterm.css';
+
+  interface Props {
+    shell?: string;
+    cwd?: string;
+    args?: string[];
+    onExit?: () => void;
+  }
+
+  let { shell, cwd, args, onExit }: Props = $props();
+
+  let terminalEl: HTMLDivElement;
+  let term: Terminal;
+  let fitAddon: FitAddon;
+  let ptyId: string | null = null;
+  let unlistenData: UnlistenFn | null = null;
+  let unlistenExit: UnlistenFn | null = null;
+  let resizeObserver: ResizeObserver | null = null;
+
+  // Catppuccin Mocha xterm theme
+  const catppuccinTheme = {
+    background: '#1e1e2e',
+    foreground: '#cdd6f4',
+    cursor: '#f5e0dc',
+    cursorAccent: '#1e1e2e',
+    selectionBackground: '#45475a',
+    selectionForeground: '#cdd6f4',
+    black: '#45475a',
+    red: '#f38ba8',
+    green: '#a6e3a1',
+    yellow: '#f9e2af',
+    blue: '#89b4fa',
+    magenta: '#f5c2e7',
+    cyan: '#94e2d5',
+    white: '#bac2de',
+    brightBlack: '#585b70',
+    brightRed: '#f38ba8',
+    brightGreen: '#a6e3a1',
+    brightYellow: '#f9e2af',
+    brightBlue: '#89b4fa',
+    brightMagenta: '#f5c2e7',
+    brightCyan: '#94e2d5',
+    brightWhite: '#a6adc8',
+  };
+
+  onMount(async () => {
+    term = new Terminal({
+      theme: catppuccinTheme,
+      fontFamily: "'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace",
+      fontSize: 13,
+      lineHeight: 1.2,
+      cursorBlink: true,
+      cursorStyle: 'block',
+      scrollback: 10000,
+      allowProposedApi: true,
+    });
+
+    fitAddon = new FitAddon();
+    term.loadAddon(fitAddon);
+    term.loadAddon(new CanvasAddon());
+    term.open(terminalEl);
+    fitAddon.fit();
+
+    const { cols, rows } = term;
+
+    // Spawn PTY
+    try {
+      ptyId = await spawnPty({ shell, cwd, args, cols, rows });
+
+      // Listen for PTY output
+      unlistenData = await onPtyData(ptyId, (data) => {
+        term.write(data);
+      });
+
+      unlistenExit = await onPtyExit(ptyId, () => {
+        term.write('\r\n\x1b[90m[Process exited]\x1b[0m\r\n');
+        onExit?.();
+      });
+
+      // Forward keyboard input to PTY
+      term.onData((data) => {
+        if (ptyId) writePty(ptyId, data);
+      });
+    } catch (e) {
+      term.write(`\x1b[31mFailed to spawn terminal: ${e}\x1b[0m\r\n`);
+    }
+
+    // Resize handling with debounce
+    let resizeTimer: ReturnType<typeof setTimeout>;
+    resizeObserver = new ResizeObserver(() => {
+      clearTimeout(resizeTimer);
+      resizeTimer = setTimeout(() => {
+        fitAddon.fit();
+        if (ptyId) {
+          const { cols, rows } = term;
+          resizePty(ptyId, cols, rows);
+        }
+      }, 100);
+    });
+    resizeObserver.observe(terminalEl);
+  });
+
+  onDestroy(async () => {
+    resizeObserver?.disconnect();
+    unlistenData?.();
+    unlistenExit?.();
+    if (ptyId) {
+      try { await killPty(ptyId); } catch { /* already dead */ }
+    }
+    term?.dispose();
+  });
+</script>
+
+<div class="terminal-container" bind:this={terminalEl}></div>
+
+<style>
+  .terminal-container {
+    width: 100%;
+    height: 100%;
+    overflow: hidden;
+  }
+
+  .terminal-container :global(.xterm) {
+    height: 100%;
+    padding: 4px;
+  }
+</style>