refactor: update managers to use RoleEnvVars

Consolidates all role startup code to use the shared RoleEnvVars()
function, ensuring consistent env vars across tmux SetEnvironment
and Claude startup command exports.

Updated:
- Mayor manager
- Deacon startup (daemon.go)
- Witness manager
- Refinery manager
- Polecat startup (daemon.go)
- BuildPolecatStartupCommand, BuildCrewStartupCommand helpers

This ensures all agents receive the same identity env vars regardless
of startup path.

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

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

internal/mayor/manager.go

@@ -94,8 +94,11 @@ func (m *Manager) Start(agentOverride string) error {
 	}
 
 	// Set environment variables (non-fatal: session works without these)
-	_ = t.SetEnvironment(sessionID, "GT_ROLE", "mayor")
-	_ = t.SetEnvironment(sessionID, "BD_ACTOR", "mayor")
+	// Use shared RoleEnvVars for consistency across all role startup paths
+	envVars := config.RoleEnvVars("mayor", "", "")
+	for k, v := range envVars {
+		_ = t.SetEnvironment(sessionID, k, v)
+	}
 
 	// Apply Mayor theming (non-fatal: theming failure doesn't affect operation)
 	theme := tmux.MayorTheme()