Summary

• Uses terminal-size package to detect actual terminal width when stdout.columns is unavailable (piped processes)
• Falls back to 80 columns only when both methods fail
• Ensures consistent terminal width detection across all code paths

Problem

When Ink's output is piped (e.g., node app.js | cat), stdout.columns returns 0 or undefined, causing layout to default to 80 columns even when the terminal is wider.

Solution

The terminal-size package can detect terminal dimensions even when stdout is piped, by checking stdin/stderr or using platform-specific methods.

Changes made:

1. Added terminal-size dependency - Zero-dependency package by @sindresorhus
2. Modified getTerminalWidth() method - Uses terminal-size as fallback:

   getTerminalWidth = () => {
       if (this.options.stdout.columns) {
           return this.options.stdout.columns;
       }
       const size = terminalSize();
       return size?.columns ?? 80;
   };

3. Updated screen reader code path - Changed direct stdout.columns access to use getTerminalWidth() for consistency

Test plan

• TypeScript compilation passes
• Linting passes
• All stdout.columns usages now go through getTerminalWidth()
• Manual test: Verified piped output (npm run example test.tsx | cat) detects actual terminal width instead of defaulting to 80

Fixes #670