feat(terminal): refactor runtime and add mobile workspace (#2280)

Replace the legacy terminal flow with a shared authenticated WebSocket
runtime used across web, desktop, relay, and mobile surfaces.

- introduce the v3 terminal protocol with scoped attachments, snapshots,
  ordered output, bounded replay history, reconnects, and explicit lifecycle
- harden PTY creation, restart, resize, close, force-kill, idle cleanup,
  shell selection, login mode, environment sanitization, and appearance sync
- add runtime-aware terminal APIs with relay authentication and Electron parity
- add a fullscreen mobile terminal workspace with touch scrolling,
  long-press selection, safe-area controls, quick keys, and Ctrl/Alt input
- add terminal selection attachments, preview detection, project actions,
  shell settings, and localized UI
- harden Ghostty rendering, resize recovery, Unicode handling, block
  characters, line height, and stale-row behavior
- remove the obsolete terminal SSE path and update reverse-proxy guidance
- expand terminal runtime, transport, input, selection, and store coverage
- avoid duplicate web builds when preparing mobile assets in root CI builds

packages/ui/src/lib/terminalTouchSelection.ts

@@ -0,0 +1,48 @@
+export type TerminalCellPosition = {
+  column: number;
+  row: number;
+};
+
+type TerminalViewportRect = {
+  left: number;
+  top: number;
+  width: number;
+  height: number;
+};
+
+export const getTerminalCellFromPoint = (
+  clientX: number,
+  clientY: number,
+  bounds: TerminalViewportRect,
+  columns: number,
+  rows: number,
+): TerminalCellPosition | null => {
+  if (bounds.width <= 0 || bounds.height <= 0 || columns <= 0 || rows <= 0) return null;
+
+  const column = Math.floor(((clientX - bounds.left) / bounds.width) * columns);
+  const row = Math.floor(((clientY - bounds.top) / bounds.height) * rows);
+
+  return {
+    column: Math.max(0, Math.min(columns - 1, column)),
+    row: Math.max(0, Math.min(rows - 1, row)),
+  };
+};
+
+export const getTerminalWordRange = (
+  cells: string[],
+  column: number,
+): { startColumn: number; endColumn: number } => {
+  const clampedColumn = Math.max(0, Math.min(cells.length - 1, column));
+  const isWordCell = (value: string | undefined) => Boolean(value && !/^\s+$/u.test(value));
+
+  if (!isWordCell(cells[clampedColumn])) {
+    return { startColumn: clampedColumn, endColumn: clampedColumn };
+  }
+
+  let startColumn = clampedColumn;
+  let endColumn = clampedColumn;
+  while (startColumn > 0 && isWordCell(cells[startColumn - 1])) startColumn -= 1;
+  while (endColumn < cells.length - 1 && isWordCell(cells[endColumn + 1])) endColumn += 1;
+
+  return { startColumn, endColumn };
+};