function calculateLeadScore(lead: LeadRecord): number {
  let score = 50;  // base score
  if (lead.email)                score += 10;
  if (lead.company)              score += 15;
  if (lead.phone)                score += 10;
  if (lead.source === 'referral') score += 15;
  // Cap at 100
  return Math.min(score, 100);
}

lead → qualified → proposal → negotiation → closed_won / closed_lost

Tab 1: Pipeline (horizontal-scroll kanban)
  └── Column per stage, cards draggable between stages

Tab 2: Leads
  └── List with lead score badge (color by tier)
  └── Filter by stage

Tab 3: Statistics
  └── Win rate (LinearProgressIndicator)
  └── Revenue breakdown per stage
  └── Lost deals analysis

final winRate = totalDeals > 0 ? wonDeals / totalDeals : 0.0;
Row(
  children: [
    Expanded(
      child: LinearProgressIndicator(
        value: winRate.clamp(0.0, 1.0),
        backgroundColor: Colors.grey.shade200,
        valueColor: AlwaysStoppedAnimation<Color>(Color(0xFF059669)),
        minHeight: 8,
      ),
    ),
    const SizedBox(width: 8),
    Text('${(winRate * 100).toStringAsFixed(1)}%'),
  ],
)

function calculateRaceScore(horse: HorseRecord): number {
  return (
    horse.recent_form_score  * 3 +   // last 3 races weighted heaviest
    horse.jockey_win_rate    * 2 +   // jockey skill
    horse.trainer_win_rate       +   // trainer skill
    horse.track_affinity             // course specialization bonus
  );
}

Color _gradeColor(String? grade) => switch (grade) {
  'G1' => Colors.red,
  'G2' => Colors.orange,
  'G3' => Colors.yellow.shade700,
  _    => Colors.grey,
};

Chip(
  label: Text(race['grade'] ?? ''),
  backgroundColor: _gradeColor(race['grade']).withValues(alpha: 0.15),
  side: BorderSide(color: _gradeColor(race['grade'])),
)

Widget _predBadge(String? result) => Container(
  padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
  decoration: BoxDecoration(
    color: switch (result) {
      'hit'    => Colors.green.withValues(alpha: 0.15),
      'miss'   => Colors.red.withValues(alpha: 0.15),
      _        => Colors.grey.withValues(alpha: 0.15),
    },
    borderRadius: BorderRadius.circular(4),
  ),
  child: Text(
    switch (result) {
      'hit'  => '✓ Hit',
      'miss' => '✗ Miss',
      _      => 'Pending',
    },
    style: TextStyle(
      fontSize: 11,
      color: switch (result) {
        'hit'  => Colors.green,
        'miss' => Colors.red,
        _      => Colors.grey,
      },
    ),
  ),
);

// WRONG — context.read after async gap
Future<void> _doSomething() async {
  await someAsyncCall();
  final service = context.read<NotificationService>(); // lint error
}

// CORRECT — extract before await
Future<void> _doSomething() async {
  final navigator = Navigator.of(context);   // before await
  final messenger = ScaffoldMessenger.of(context);
  await someAsyncCall();
  navigator.pop();           // safe — no context reference
  messenger.showSnackBar(…);
}