hub: ASCII banner, MOTD, ctrl+c→main-menu everywhere, Shell option

UX pass on the single-login hub:

- ctrl+c now always returns to the main menu from any in-hub plugin/game
  instead of being forwarded. Fixes the snake game being un-exitable (it never
  handled ctrl+c) and makes "back to menu" uniform across every screen.
- profullstack.com ASCII banner rendered atop the hub menu and the join@
  onboarding flow.
- MOTD box under the title (guest vs member tailored; AGENTBBS_MOTD overrides
  the body).
- New "Shell" hub entry drops straight into `bash -l` in the member's pod; the
  existing "Pod" entry now attaches to the pod's main session.
- Polish: highlighted selection + ❯ cursor, brand colors, clearer footer.

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

cmd/agentbbs/main.go

@@ -42,6 +42,7 @@ import (
 	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
 	"github.com/charmbracelet/log"
 	"github.com/charmbracelet/ssh"
 	"github.com/charmbracelet/wish"
@@ -328,6 +329,26 @@ func (a *app) router() wish.Middleware {
 	}
 }
 
+// bbsBanner is the ASCII brand mark shown atop the hub menu and the join@ flow.
+const bbsBanner = "" +
+	"┌─┐┬─┐┌─┐┌─┐┬ ┬┬  ┬  ┌─┐┌┬┐┌─┐┌─┐┬┌─\n" +
+	"├─┘├┬┘│ │├┤ │ ││  │  └─┐ │ ├─┤│  ├┴┐\n" +
+	"┴  ┴└─└─┘└  └─┘┴─┘┴─┘└─┘ ┴ ┴ ┴└─┘┴ ┴ .com"
+
+var bannerStyle = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("#38bdf8"))
+
+// hubMOTD is the welcome message shown in a box on the hub menu. The body is
+// operator-overridable via AGENTBBS_MOTD; it is tailored for guests vs members.
+func (a *app) hubMOTD(u auth.User) string {
+	body := env("AGENTBBS_MOTD",
+		"A terminal BBS for humans & AI agents.\nGames · IRC · News · a Linux pod · your own homepage.")
+	if u.Kind == auth.Guest {
+		return "You're browsing as a guest.\n" + body +
+			"\nssh join@" + a.host + " to claim a username, a pod & a homepage."
+	}
+	return "Welcome back, " + u.Name + ".\n" + body
+}
+
 // teaHandler builds the hub model for guests, members, and agents.
 func (a *app) teaHandler(s ssh.Session) (tea.Model, []tea.ProgramOption) {
 	fp := auth.Fingerprint(s.PublicKey())
@@ -383,7 +404,7 @@ func (a *app) teaHandler(s ssh.Session) (tea.Model, []tea.ProgramOption) {
 		// URL works the moment a member first signs in.
 		seedHomepage(filepath.Join(ctx.DataDir, "public_html"), u.Name, a.host)
 	}
-	return hub.New(u, ctx, a.enabledPlugins(), a.sessionApps(s, su, guest)), []tea.ProgramOption{tea.WithAltScreen()}
+	return hub.New(u, ctx, a.enabledPlugins(), a.sessionApps(s, su, guest), bbsBanner, a.hubMOTD(u)), []tea.ProgramOption{tea.WithAltScreen()}
 }
 
 // sessionExec adapts a func to tea.ExecCommand so the hub can run a
@@ -416,9 +437,15 @@ func (a *app) sessionApps(s ssh.Session, su store.User, guest bool) []hub.Sessio
 	case a.pods == nil:
 		podLock = "pods are temporarily unavailable on this host"
 	}
+	apps = append(apps, hub.SessionApp{
+		Title:       "Shell",
+		Description: "drop straight into a bash shell in your pod",
+		Locked:      podLock,
+		Cmd:         sessionExec{run: func() error { return a.pods.Exec(s, su.Name, []string{"bash", "-l"}) }},
+	})
 	apps = append(apps, hub.SessionApp{
 		Title:       "Pod",
-		Description: "your own Linux pod — a full shell",
+		Description: "your own Linux pod — attach to its main session",
 		Locked:      podLock,
 		Cmd:         sessionExec{run: func() error { return a.pods.Attach(s, su.Name) }},
 	})
@@ -521,6 +548,7 @@ func (a *app) handleJoin(s ssh.Session) {
 		_ = s.Exit(1)
 		return
 	}
+	wish.Println(s, "\n"+bannerStyle.Render(bbsBanner))
 	in := bufio.NewReader(s)
 
 	u, found, err := a.st.UserByFingerprint(fp)

internal/hub/hub.go

@@ -12,6 +12,7 @@ package hub
 
 import (
 	"fmt"
+	"strings"
 
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
@@ -23,8 +24,15 @@ import (
 var (
 	titleStyle  = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("#4ade80"))
 	dimStyle    = lipgloss.NewStyle().Foreground(lipgloss.Color("241"))
-	cursorStyle = lipgloss.NewStyle().Foreground(lipgloss.Color("#4ade80"))
+	cursorStyle = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("#4ade80"))
+	selStyle    = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("#e2e8f0"))
 	lockStyle   = lipgloss.NewStyle().Foreground(lipgloss.Color("203"))
+	bannerStyle = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("#38bdf8"))
+	motdStyle   = lipgloss.NewStyle().
+			Border(lipgloss.RoundedBorder()).
+			BorderForeground(lipgloss.Color("#4ade80")).
+			Foreground(lipgloss.Color("252")).
+			Padding(0, 1)
 	frameStyle = lipgloss.NewStyle().Padding(1, 2)
 )
 
@@ -52,6 +60,8 @@ type Model struct {
 	ctx     plugin.Context
 	plugins []plugin.Plugin
 	apps    []SessionApp
+	banner  string // ASCII brand banner shown above the menu (may be empty)
+	motd    string // message-of-the-day shown in a box under the title (may be empty)
 
 	cursor int
 	active tea.Model
@@ -61,9 +71,10 @@ type Model struct {
 }
 
 // New builds a hub for one session. apps are terminal-takeover features listed
-// after the in-hub plugins (may be nil).
+// after the in-hub plugins (may be nil). banner is an ASCII brand banner and
-func New(user auth.User, ctx plugin.Context, plugins []plugin.Plugin, apps []SessionApp) Model {
+// motd a short welcome message; either may be empty.
-	return Model{user: user, ctx: ctx, plugins: plugins, apps: apps}
+func New(user auth.User, ctx plugin.Context, plugins []plugin.Plugin, apps []SessionApp, banner, motd string) Model {
+	return Model{user: user, ctx: ctx, plugins: plugins, apps: apps, banner: banner, motd: motd}
 }
 
 func (m Model) Init() tea.Cmd { return nil }
@@ -85,8 +96,15 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		return m, nil
 	}
 
-	// A plugin owns the session until it emits ExitMsg (PRD §4.3).
+	// A plugin owns the session until it emits ExitMsg (PRD §4.3) — except
+	// ctrl+c, which the hub always reclaims so EVERY menu/game has a guaranteed
+	// way back to the main menu (some plugins, e.g. snake, don't handle it).
 	if m.active != nil {
+		if k, ok := msg.(tea.KeyMsg); ok && k.String() == "ctrl+c" {
+			m.active = nil
+			m.note = "← back to main menu"
+			return m, nil
+		}
 		if _, ok := msg.(plugin.ExitMsg); ok {
 			m.active = nil
 			return m, nil
@@ -147,15 +165,23 @@ func (m Model) View() string {
 	if m.active != nil {
 		return m.active.View()
 	}
+	var b strings.Builder
+	if m.banner != "" {
+		b.WriteString(bannerStyle.Render(m.banner) + "\n\n")
+	}
 	who := fmt.Sprintf("%s (%s)", m.user.Name, m.user.Kind)
-	s := titleStyle.Render("AgentBBS") + dimStyle.Render("  ·  "+who) + "\n\n"
+	b.WriteString(titleStyle.Render("AgentBBS") + dimStyle.Render("  ·  "+who) + "\n")
+	if m.motd != "" {
+		b.WriteString("\n" + motdStyle.Render(m.motd) + "\n")
+	}
+	b.WriteString("\n")
 	row := 0
 	for _, p := range m.plugins {
 		label := p.Title()
 		if p.RequiresAuth() && m.user.Kind == auth.Guest {
 			label += lockStyle.Render("  [members]")
 		}
-		s += m.renderRow(row, label, p.Description())
+		b.WriteString(m.renderRow(row, label, p.Description()))
 		row++
 	}
 	for _, app := range m.apps {
@@ -163,21 +189,23 @@ func (m Model) View() string {
 		if app.Locked != "" {
 			label += lockStyle.Render("  [locked]")
 		}
-		s += m.renderRow(row, label, app.Description)
+		b.WriteString(m.renderRow(row, label, app.Description))
 		row++
 	}
-	s += "\n" + dimStyle.Render("↑/↓ move · enter select · q quit")
+	b.WriteString("\n" + dimStyle.Render("↑/↓ move · enter select · ctrl+c back · q quit"))
 	if m.note != "" {
-		s += "\n" + lockStyle.Render(m.note)
+		b.WriteString("\n" + lockStyle.Render(m.note))
 	}
-	return frameStyle.Render(s)
+	return frameStyle.Render(b.String())
 }
 
-// renderRow renders one menu line with the cursor and dimmed description.
+// renderRow renders one menu line with the cursor and dimmed description. The
+// selected row's cursor and label are highlighted.
 func (m Model) renderRow(i int, label, desc string) string {
 	cur := "  "
 	if i == m.cursor {
-		cur = cursorStyle.Render("> ")
+		cur = cursorStyle.Render("❯ ")
+		label = selStyle.Render(label)
 	}
 	return fmt.Sprintf("%s%s\n  %s\n", cur, label, dimStyle.Render(desc))
 }