fix: clean newline paste thingy

ui-tui/src/lib/text.test.ts

@@ -0,0 +1,18 @@
+import { describe, expect, it } from 'vitest'
+
+import { stripTrailingPasteNewlines } from './text.js'
+
+describe('stripTrailingPasteNewlines', () => {
+  it('removes trailing newline runs from pasted text', () => {
+    expect(stripTrailingPasteNewlines('alpha\n')).toBe('alpha')
+    expect(stripTrailingPasteNewlines('alpha\nbeta\n\n')).toBe('alpha\nbeta')
+  })
+
+  it('preserves interior newlines', () => {
+    expect(stripTrailingPasteNewlines('alpha\nbeta\ngamma')).toBe('alpha\nbeta\ngamma')
+  })
+
+  it('preserves newline-only pastes', () => {
+    expect(stripTrailingPasteNewlines('\n\n')).toBe('\n\n')
+  })
+})