refactor: 提取共享 getStatColor、移除 deprecated EVOLUTION_CHAINS

- 新增 ui/shared.ts 统一 getStatColor 函数
- CompanionCard/SpeciesDetail 改用共享函数，消除重复
- 移除 data/evolution.ts 中已废弃的 EVOLUTION_CHAINS 常量
- 清理 index.ts 导出

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/pokemon/src/ui/shared.ts

@@ -0,0 +1,14 @@
+import type { Color } from '@anthropic/ink'
+
+const STAT_COLORS: Record<string, Color> = {
+	hp: 'ansi:green',
+	attack: 'ansi:red',
+	defense: 'ansi:yellow',
+	spAtk: 'ansi:blue',
+	spDef: 'ansi:magenta',
+	speed: 'ansi:cyan',
+}
+
+export function getStatColor(stat: string): Color {
+	return STAT_COLORS[stat] ?? 'ansi:white'
+}