The terminal's New forge screen picks a template, Blank or Starter app, as MCP spawn's `template` does #7934

Intent: making a forge from the terminal offers the same starting points as MCP spawn.

Today src/tui/screens/newforge.ts has name, apps, budget and size fields; no template.

Done:

• [ ] A Template field after Size, with choices from TEMPLATES (left and right choose, or type the id), Blank by default, its hint the chosen template's says sentence.
• [ ] The submit sends template only when it is not the default; an unknown id comes back as the door's field refusal on that field, as size does.
• [ ] The plan lines say Template: Starter app. when one other than Blank is chosen.
• [ ] A test in test/tui-newforge.test.ts fails without the change: choosing starter sends template: "starter" and the plan names it; the default sends no template.
• [ ] By eye in the terminal: the palette's New forge shows the field.

Files: src/tui/screens/newforge.ts, test/tui-newforge.test.ts.