feat: mail uses wisps for ephemeral orchestration messages (gt-lg66)

Add dual-inbox architecture where ephemeral messages go to
.beads-wisp/.beads/ instead of .beads/. Lifecycle messages
(POLECAT_STARTED, NUDGE, etc.) auto-detect as ephemeral.

Changes:
- Add Ephemeral and Source fields to mail.Message
- Add --ephemeral flag to gt mail send
- Router auto-detects lifecycle message patterns
- Mailbox merges messages from both persistent and wisp storage
- Inbox displays (ephemeral) indicator for wisp messages
- Delete/archive works for both message types

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

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

internal/mail/mailbox.go

@@ -23,6 +23,7 @@ type Mailbox struct {
 	identity string // beads identity (e.g., "gastown/polecats/Toast")
 	workDir  string // directory to run bd commands in
 	beadsDir string // explicit .beads directory path (set via BEADS_DIR)
+	wispDir  string // .beads-wisp directory for ephemeral messages
 	path     string // for legacy JSONL mode (crew workers)
 	legacy   bool   // true = use JSONL files, false = use beads
 }
@@ -48,20 +49,26 @@ func NewMailboxBeads(identity, workDir string) *Mailbox {
 // NewMailboxFromAddress creates a beads-backed mailbox from a GGT address.
 func NewMailboxFromAddress(address, workDir string) *Mailbox {
 	beadsDir := filepath.Join(workDir, ".beads")
+	// Wisp directory is .beads-wisp/.beads (bd init creates .beads/ subdirectory)
+	wispDir := filepath.Join(workDir, ".beads-wisp", ".beads")
 	return &Mailbox{
 		identity: addressToIdentity(address),
 		workDir:  workDir,
 		beadsDir: beadsDir,
+		wispDir:  wispDir,
 		legacy:   false,
 	}
 }
 
 // NewMailboxWithBeadsDir creates a mailbox with an explicit beads directory.
 func NewMailboxWithBeadsDir(address, workDir, beadsDir string) *Mailbox {
+	// Derive wispDir from beadsDir (.beads-wisp/.beads sibling structure)
+	wispDir := filepath.Join(filepath.Dir(beadsDir), ".beads-wisp", ".beads")
 	return &Mailbox{
 		identity: addressToIdentity(address),
 		workDir:  workDir,
 		beadsDir: beadsDir,
+		wispDir:  wispDir,
 		legacy:   false,
 	}
 }
@@ -85,6 +92,29 @@ func (m *Mailbox) List() ([]*Message, error) {
 }
 
 func (m *Mailbox) listBeads() ([]*Message, error) {
+	// Query persistent beads
+	persistentMsgs, err := m.listFromDir(m.beadsDir, SourcePersistent)
+	if err != nil {
+		return nil, err
+	}
+
+	// Query wisp beads (ignore errors for missing dir)
+	var wispMsgs []*Message
+	if m.wispDir != "" {
+		wispMsgs, _ = m.listFromDir(m.wispDir, SourceWisp)
+	}
+
+	// Merge and sort by timestamp (newest first)
+	all := append(persistentMsgs, wispMsgs...)
+	sort.Slice(all, func(i, j int) bool {
+		return all[i].Timestamp.After(all[j].Timestamp)
+	})
+
+	return all, nil
+}
+
+// listFromDir queries messages from a specific beads directory.
+func (m *Mailbox) listFromDir(beadsDir string, source MessageSource) ([]*Message, error) {
 	// bd list --type=message --assignee=<identity> --json --status=open
 	cmd := exec.Command("bd", "list",
 		"--type", "message",
@@ -94,7 +124,7 @@ func (m *Mailbox) listBeads() ([]*Message, error) {
 	)
 	cmd.Dir = m.workDir
 	cmd.Env = append(cmd.Environ(),
-		"BEADS_DIR="+m.beadsDir,
+		"BEADS_DIR="+beadsDir,
 	)
 
 	var stdout, stderr bytes.Buffer
@@ -119,10 +149,13 @@ func (m *Mailbox) listBeads() ([]*Message, error) {
 		return nil, err
 	}
 
-	// Convert to GGT messages
+	// Convert to GGT messages and set source
 	var messages []*Message
 	for _, bm := range beadsMsgs {
-		messages = append(messages, bm.ToMessage())
+		msg := bm.ToMessage()
+		msg.Source = source
+		msg.Ephemeral = (source == SourceWisp)
+		messages = append(messages, msg)
 	}
 
 	return messages, nil
@@ -193,9 +226,28 @@ func (m *Mailbox) Get(id string) (*Message, error) {
 }
 
 func (m *Mailbox) getBeads(id string) (*Message, error) {
+	// Try persistent first
+	msg, err := m.getFromDir(id, m.beadsDir, SourcePersistent)
+	if err == nil {
+		return msg, nil
+	}
+
+	// Try wisp storage
+	if m.wispDir != "" {
+		msg, err = m.getFromDir(id, m.wispDir, SourceWisp)
+		if err == nil {
+			return msg, nil
+		}
+	}
+
+	return nil, ErrMessageNotFound
+}
+
+// getFromDir retrieves a message from a specific beads directory.
+func (m *Mailbox) getFromDir(id, beadsDir string, source MessageSource) (*Message, error) {
 	cmd := exec.Command("bd", "show", id, "--json")
 	cmd.Dir = m.workDir
-	cmd.Env = append(cmd.Environ(), "BEADS_DIR="+m.beadsDir)
+	cmd.Env = append(cmd.Environ(), "BEADS_DIR="+beadsDir)
 
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout
@@ -221,7 +273,10 @@ func (m *Mailbox) getBeads(id string) (*Message, error) {
 		return nil, ErrMessageNotFound
 	}
 
-	return bms[0].ToMessage(), nil
+	msg := bms[0].ToMessage()
+	msg.Source = source
+	msg.Ephemeral = (source == SourceWisp)
+	return msg, nil
 }
 
 func (m *Mailbox) getLegacy(id string) (*Message, error) {
@@ -246,9 +301,28 @@ func (m *Mailbox) MarkRead(id string) error {
 }
 
 func (m *Mailbox) markReadBeads(id string) error {
+	// Try persistent first
+	err := m.closeInDir(id, m.beadsDir)
+	if err == nil {
+		return nil
+	}
+
+	// Try wisp storage
+	if m.wispDir != "" {
+		err = m.closeInDir(id, m.wispDir)
+		if err == nil {
+			return nil
+		}
+	}
+
+	return ErrMessageNotFound
+}
+
+// closeInDir closes a message in a specific beads directory.
+func (m *Mailbox) closeInDir(id, beadsDir string) error {
 	cmd := exec.Command("bd", "close", id)
 	cmd.Dir = m.workDir
-	cmd.Env = append(cmd.Environ(), "BEADS_DIR="+m.beadsDir)
+	cmd.Env = append(cmd.Environ(), "BEADS_DIR="+beadsDir)
 
 	var stderr bytes.Buffer
 	cmd.Stderr = &stderr