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/prime.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/steveyegge/gastown/internal/beads"
+	"github.com/steveyegge/gastown/internal/constants"
 	"github.com/steveyegge/gastown/internal/events"
 	"github.com/steveyegge/gastown/internal/lock"
 	"github.com/steveyegge/gastown/internal/style"
@@ -871,7 +872,7 @@ func outputWitnessPatrolContext(ctx RoleContext) {
 		PatrolMolName:   "mol-witness-patrol",
 		BeadsDir:        ctx.WorkDir,
 		Assignee:        ctx.Rig + "/witness",
-		HeaderEmoji:     "👁",
+		HeaderEmoji:     constants.EmojiWitness,
 		HeaderTitle:     "Witness Patrol Status",
 		CheckInProgress: true,
 		WorkLoopSteps: []string{