Improve error message for missing franc-min dependency

[Copilot]

The error handler for missing franc-min logged "franc-min not available, using feed-declared language only" without telling users how to fix it.

Changes

• Enhanced error message to include actionable resolution steps
• Message now explicitly instructs users to run npm install when the package is missing

} catch (e) {
  console.error('WARNING: franc-min package not found. Language detection will be limited to feed-declared languages only.');
  console.error('To enable automatic language detection, please run: npm install');
  detectLang = () => null;
}

This addresses the review feedback that error messages should be informative and include instructions for resolution.

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[Copilot]

Pull request overview

Updates the runtime warning emitted when the optional franc-min dependency is unavailable, so users get actionable guidance to restore automatic language detection.

Changes:

• Replaced the generic franc-min not available... log with a clearer warning.
• Added an instruction telling users to run npm install to resolve the missing dependency.

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[Copilot]

The catch (e) currently assumes any failure means franc-min is missing and logs "package not found". If require('franc-min') throws for another reason (e.g., corrupted install or unexpected runtime error), this message will be misleading and the real error will be masked. Consider checking e.code === 'MODULE_NOT_FOUND' (and that the message references franc-min) before logging this, and otherwise rethrow or log the original error details.

Suggested change

	console.error('WARNING: franc-min package not found. Language detection will be limited to feed-declared languages only.');
	console.error('To enable automatic language detection, please run: npm install');
	if (e && e.code === 'MODULE_NOT_FOUND' && (e.message || '').includes('franc-min')) {
	console.error('WARNING: franc-min package not found. Language detection will be limited to feed-declared languages only.');
	console.error('To enable automatic language detection, please run: npm install');
	} else {
	console.error('ERROR: Failed to initialize franc-min language detection. Falling back to feed-declared languages only.');
	console.error(e);
	}