spawn: Add work instruction + export SessionName

- Export session.Manager.SessionName for spawn.go access
- Add --address alias for --identity in mail inbox/check
- Send explicit work instruction to polecat after spawn
- Add CapturePaneLines and WaitForClaudeReady helpers (unused for now)
- Proper solution filed as gt-hb0 (needs Witness/Deacon AI monitoring)

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

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

internal/cmd/mail.go

@@ -177,6 +177,7 @@ func init() {
 	mailInboxCmd.Flags().BoolVar(&mailInboxJSON, "json", false, "Output as JSON")
 	mailInboxCmd.Flags().BoolVarP(&mailInboxUnread, "unread", "u", false, "Show only unread messages")
 	mailInboxCmd.Flags().StringVar(&mailInboxIdentity, "identity", "", "Explicit identity for inbox (e.g., gastown/Toast)")
+	mailInboxCmd.Flags().StringVar(&mailInboxIdentity, "address", "", "Alias for --identity")
 
 	// Read flags
 	mailReadCmd.Flags().BoolVar(&mailReadJSON, "json", false, "Output as JSON")
@@ -185,6 +186,7 @@ func init() {
 	mailCheckCmd.Flags().BoolVar(&mailCheckInject, "inject", false, "Output format for Claude Code hooks")
 	mailCheckCmd.Flags().BoolVar(&mailCheckJSON, "json", false, "Output as JSON")
 	mailCheckCmd.Flags().StringVar(&mailCheckIdentity, "identity", "", "Explicit identity for inbox (e.g., gastown/Toast)")
+	mailCheckCmd.Flags().StringVar(&mailCheckIdentity, "address", "", "Alias for --identity")
 
 	// Thread flags
 	mailThreadCmd.Flags().BoolVar(&mailThreadJSON, "json", false, "Output as JSON")