Clean up TUI package and refactor component structure

- Remove old TUI implementation and components (LoadingAnimation, MarkdownComponent, TextComponent, TextEditor, WhitespaceComponent)
- Rename components-new to components with new API (Loader, Markdown, Text, Editor, Spacer)
- Move Text and Input components to separate files in src/components/
- Add render caching to Text component (similar to Markdown)
- Add proper ANSI code handling in Text component using stripVTControlCharacters
- Update coding-agent to use new TUI API (requires ProcessTerminal, uses custom Editor subclass for key handling)
- Remove old test files, keep only chat-simple.ts and virtual-terminal.ts
- Update README.md with new minimal API documentation
- Switch from tsc to tsgo for type checking
- Update package dependencies across monorepo

packages/tui/src/components/spacer.ts

@@ -0,0 +1,24 @@
+import type { Component } from "../tui.js";
+
+/**
+ * Spacer component that renders empty lines
+ */
+export class Spacer implements Component {
+	private lines: number;
+
+	constructor(lines: number = 1) {
+		this.lines = lines;
+	}
+
+	setLines(lines: number): void {
+		this.lines = lines;
+	}
+
+	render(_width: number): string[] {
+		const result: string[] = [];
+		for (let i = 0; i < this.lines; i++) {
+			result.push("");
+		}
+		return result;
+	}
+}