Centralize role emojis: Witness 👁→🦉, Deacon 🦉→🐺

Added centralized emoji constants in internal/constants/constants.go
for easy customization. Updated all files that hardcoded role emojis
to use the new constants.

Changes:
- Witness emoji: 👁 (eye) → 🦉 (owl) - less creepy, matches visual identity
- Deacon emoji: 🦉 (owl) → 🐺 (wolf) - matches hierarchy prompt (wolf in engine room)
- Added RoleEmoji() helper function for string-based lookups
- Maintained backwards compatibility with legacy role names

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/cmd/agents.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	"github.com/spf13/cobra"
+	"github.com/steveyegge/gastown/internal/constants"
 	"github.com/steveyegge/gastown/internal/lock"
 	"github.com/steveyegge/gastown/internal/style"
 	"github.com/steveyegge/gastown/internal/tmux"
@@ -47,13 +48,14 @@ var AgentTypeColors = map[AgentType]string{
 }
 
 // AgentTypeIcons maps agent types to display icons.
+// Uses centralized emojis from constants package.
 var AgentTypeIcons = map[AgentType]string{
-	AgentMayor:    "🎩",
-	AgentDeacon:   "🦉",
-	AgentWitness:  "👁",
-	AgentRefinery: "🏭",
-	AgentCrew:     "👷",
-	AgentPolecat:  "😺",
+	AgentMayor:    constants.EmojiMayor,
+	AgentDeacon:   constants.EmojiDeacon,
+	AgentWitness:  constants.EmojiWitness,
+	AgentRefinery: constants.EmojiRefinery,
+	AgentCrew:     constants.EmojiCrew,
+	AgentPolecat:  constants.EmojiPolecat,
 }
 
 var agentsCmd = &cobra.Command{