TypeScript AppHost: support terminal dimension options with withTerminal

## Summary
TypeScript AppHost currently supports withTerminal() but does not expose an options overload to set initial terminal dimensions (columns/rows), unlike C# WithTerminal(options => ...).

## Expected behavior
TypeScript AppHost should support configuring terminal dimensions for parity with C#.

## Current behavior
Only parameterless withTerminal() is available in TypeScript samples/APIs, so users cannot configure dimensions from TS AppHost code.

## Context
- Source feature PR: microsoft/aspire#17866
- Docs PR where this gap was identified: microsoft/aspire.dev#1244

## Proposed direction
Add a TypeScript API shape for terminal options, for example: await resource.withTerminal({ columns: 100, rows: 28 });

(or an equivalent typed options API consistent with existing TS AppHost patterns).

Start by locating the TypeScript AppHost implementation and existing withTerminal() samples or API definitions. Compare the TypeScript shape with C# WithTerminal options and the referenced source feature PR, then add a typed dimensions API and verify that columns and rows can be configured as described.

Written by the indexing model from the issue text.