feat(ui): upgrade @lobehub/icons to v5 and update agent icon colors

Upgrade @lobehub/icons from v4 to v5.3.0, adopt new icon components (ClaudeCode, Codex, GeminiCLI) with Color variants, and align fallback AGENT_COLORS with official brand colors.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/lib/types.ts

@@ -245,10 +245,10 @@ export const AGENT_LABELS: Record<AgentType, string> = {
 }
 
 export const AGENT_COLORS: Record<AgentType, string> = {
-  claude_code: "bg-orange-500",
-  codex: "bg-green-500",
-  open_code: "bg-blue-500",
-  gemini: "bg-blue-400",
+  claude_code: "bg-[#D97757]",
+  codex: "bg-[#7A9DFF]",
+  open_code: "bg-black",
+  gemini: "bg-[#3186FF]",
   open_claw: "bg-emerald-600",
   cline: "bg-purple-500",
 }