Add AgentMail: paid-member mailbox reader (TUI + bot mode) on the BBS

internal/mailbox is a transport-agnostic mail client for Founding Lifetime
members: read, search, compose, send, reply, flag, delete.

- types/transport/client: paid-gated facade returning JSON-serializable
  structs (same shapes as @logicsrc/plugin-agentmail)
- memory.go: in-memory transport (tests/dev/reference) + tests
- imap.go/smtp.go: real backend — go-imap/v2 (Dovecot IMAP, master-user
  login) + net/smtp submission via the co-located relay; go-message parses
  bodies/attachments
- reader_tui.go: Bubble Tea reader for humans (list/read/flag/delete)
- bot.go: JSON in/out mode for agents (ssh mail@host list|read|send|…)
- wired as the paid "Mail" hub entry and the ssh mail@ route + auth.MailNames

Connects to the self-hosted Mailu stack at mail.profullstack.com /
smtp.profullstack.com. Rebased onto main; build + vet + tests clean (Go 1.26).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

internal/mailbox/mailbox_test.go

@@ -0,0 +1,144 @@
+package mailbox
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+)
+
+func seeded() *MemoryTransport {
+	m := NewMemoryTransport()
+	m.Add(Message{MessageSummary: MessageSummary{UID: 1, Mailbox: Inbox, From: Address{Name: "Carol", Address: "carol@example.com"}, Subject: "Welcome", Date: time.Date(2026, 6, 1, 10, 0, 0, 0, time.UTC)}, Text: "hi alice"})
+	m.Add(Message{MessageSummary: MessageSummary{UID: 2, Mailbox: Inbox, From: Address{Address: "deploy@ci.example.com"}, Subject: "Build passed", Date: time.Date(2026, 6, 2, 10, 0, 0, 0, time.UTC)}, Text: "all green"})
+	return m
+}
+
+func paidClient(t Transport) *Client {
+	return NewClient(t, Identity{Name: "alice", Paid: true}, "mail.profullstack.com", 50)
+}
+
+func TestParseFormatAddress(t *testing.T) {
+	a := ParseAddress("Ada Lovelace <ada@x.com>")
+	if a.Name != "Ada Lovelace" || a.Address != "ada@x.com" {
+		t.Fatalf("parse named: %+v", a)
+	}
+	if got := ParseAddress("ada@x.com"); got.Address != "ada@x.com" || got.Name != "" {
+		t.Fatalf("parse bare: %+v", got)
+	}
+	if got := FormatAddress(Address{Name: "Doe, John", Address: "j@x.com"}); got != `"Doe, John" <j@x.com>` {
+		t.Fatalf("format specials: %q", got)
+	}
+}
+
+func TestValidEmailAndDraft(t *testing.T) {
+	if !ValidEmail("a@b.com") || ValidEmail("nope") {
+		t.Fatal("ValidEmail")
+	}
+	if _, err := NormalizeDraft(Draft{Subject: "x", Text: "y"}); err == nil {
+		t.Fatal("expected error for no recipients")
+	}
+	d, err := NormalizeDraft(Draft{To: []Address{{Address: " a@b.com "}}, Subject: "  hi  ", Text: "z"})
+	if err != nil || len(d.To) != 1 || d.To[0].Address != "a@b.com" || d.Subject != "hi" {
+		t.Fatalf("normalize: %+v err=%v", d, err)
+	}
+}
+
+func TestGate(t *testing.T) {
+	c := NewClient(seeded(), Identity{Name: "bob", Paid: false}, "mail.profullstack.com", 0)
+	if _, err := c.Inbox(context.Background(), 0); !errors.Is(err, ErrNotPaid) {
+		t.Fatalf("expected ErrNotPaid, got %v", err)
+	}
+}
+
+// Inbox is a thin helper used in tests and bot mode.
+func (c *Client) Inbox(ctx context.Context, limit int) ([]MessageSummary, error) {
+	return c.List(ctx, Inbox, limit)
+}
+
+func TestListNewestFirst(t *testing.T) {
+	c := paidClient(seeded())
+	got, err := c.List(context.Background(), Inbox, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 2 || got[0].UID != 2 {
+		t.Fatalf("expected newest first [2,1], got %+v", got)
+	}
+}
+
+func TestReadMarksSeenAndPeek(t *testing.T) {
+	tr := seeded()
+	c := paidClient(tr)
+	if _, ok, _ := c.Read(context.Background(), Inbox, 1, false); !ok {
+		t.Fatal("read 1")
+	}
+	if m, _, _ := tr.ReadMessage(context.Background(), Inbox, 1); !m.Seen {
+		t.Fatal("uid 1 should be seen")
+	}
+	if _, _, _ = c.Read(context.Background(), Inbox, 2, true); true {
+		if m, _, _ := tr.ReadMessage(context.Background(), Inbox, 2); m.Seen {
+			t.Fatal("peek must not mark seen")
+		}
+	}
+	if _, ok, _ := c.Read(context.Background(), Inbox, 999, false); ok {
+		t.Fatal("unknown uid should be ok=false")
+	}
+}
+
+func TestSearch(t *testing.T) {
+	c := paidClient(seeded())
+	hits, _ := c.Search(context.Background(), "green", "", 0)
+	if len(hits) != 1 || hits[0].UID != 2 {
+		t.Fatalf("search green: %+v", hits)
+	}
+	hits, _ = c.Search(context.Background(), "carol@example.com", "", 0)
+	if len(hits) != 1 || hits[0].UID != 1 {
+		t.Fatalf("search sender: %+v", hits)
+	}
+}
+
+func TestSendAndReply(t *testing.T) {
+	tr := seeded()
+	c := paidClient(tr)
+	res, err := c.Send(context.Background(), Draft{To: []Address{{Address: "carol@example.com"}}, Subject: "  Hi  ", Text: "yo"})
+	if err != nil || res.MessageID == "" {
+		t.Fatalf("send: %v", err)
+	}
+	sent, _ := tr.ListMessages(context.Background(), ListOptions{Mailbox: Sent})
+	if len(sent) != 1 || sent[0].From.Address != "alice@mail.profullstack.com" || sent[0].Subject != "Hi" {
+		t.Fatalf("sent: %+v", sent)
+	}
+
+	orig, _, _ := c.Read(context.Background(), Inbox, 1, true)
+	if _, err := c.Reply(context.Background(), orig, "thanks", false); err != nil {
+		t.Fatal(err)
+	}
+	sent, _ = tr.ListMessages(context.Background(), ListOptions{Mailbox: Sent})
+	var re MessageSummary
+	for _, s := range sent {
+		if s.Subject == "Re: Welcome" {
+			re = s
+		}
+	}
+	if re.Subject != "Re: Welcome" || re.To[0].Address != "carol@example.com" {
+		t.Fatalf("reply: %+v", sent)
+	}
+}
+
+func TestFlagAndDelete(t *testing.T) {
+	tr := seeded()
+	c := paidClient(tr)
+	if err := c.Flag(context.Background(), Inbox, 1, true); err != nil {
+		t.Fatal(err)
+	}
+	if m, _, _ := tr.ReadMessage(context.Background(), Inbox, 1); !m.Flagged {
+		t.Fatal("uid 1 should be flagged")
+	}
+	if err := c.Delete(context.Background(), Inbox, 1); err != nil {
+		t.Fatal(err)
+	}
+	if _, ok, _ := tr.ReadMessage(context.Background(), Inbox, 1); ok {
+		t.Fatal("uid 1 should be deleted")
+	}
+}