feat: Add visual identity system for Orders

[madjin]

Summary

Each Order gets unique visual identity elements for UI display.

Order Colors

Order	Primary Color	Accent	Sigil
Builder	Blue (#3B82F6)	Steel	hammer-wrench
Hunter	Orange (#F97316)	Bronze	crosshairs
Scribe	Purple (#8B5CF6)	Gold	book-open
Maintainer	Green (#22C55E)	Silver	shield-check
Machine	Gray (#6B7280)	Neon	cpu

API Additions

{
  "characterSheet": {
    "characterClass": "Builder",
    "order": {
      "name": "Builder",
      "color": "#3B82F6",
      "accent": "#94A3B8",
      "sigil": "hammer-wrench",
      "motto": "We build the future"
    }
  }
}

Acceptance Criteria

• Define color palette for each Order
• Add sigil icons (Lucide icons)
• Add order metadata to API responses
• Update profile page with Order visuals
• Leaderboard badges with Order colors

Related

• Depends on feat: Implement full Orders & Evolution class tree #194 (Orders & Evolution system)