OpenTerminal v0.2.1: terminal suite with SSH, split panes, themes and keyword highlighting

- Local terminal (node-pty) + SSH sessions (ssh2) with unified data plane
- dockview split panes, per-group '+' tab bar button, layout templates
- Session replay buffer (late-subscriber catch-up), host key pinning,
  credential encryption via safeStorage
- 12 builtin themes + custom theme editor, system font enumeration
- Keyword highlighting: regex rules with priority, ANSI truecolor injection,
  chunk-boundary-safe stream (carry-over of partial escape sequences)
- Dark antd theme app-wide, settings dialog redesign, error boundary
- Tests: ssh loopback, session e2e, highlight split-chunk regression

tests/electron-stub.cjs

@@ -0,0 +1,12 @@
+// Minimal electron stub for bundling src/main/pty.ts under plain Node
+// (tests/ssh-session-e2e.mjs). Only what broadcast.ts touches.
+module.exports = {
+  BrowserWindow: {
+    getAllWindows: () => []
+  },
+  app: {},
+  ipcMain: {},
+  safeStorage: {
+    isEncryptionAvailable: () => false
+  }
+}