Video calls (PairUX→ASCII), agent@ chat, and finger routes

ssh video-<code>@ joins a PairUX/LiveKit call rendered as truecolor
ASCII (▀ half-blocks, 2 pixels per cell); video@ prompts for a code.
Codes are minted by PairUX only. Pipeline: VP8 RTP → PLI keyframe
requests → ivfwriter remux → ffmpeg decode/scale → RGB24 → ANSI →
bubbletea over the SSH PTY. Subscriber-only, no audio in v1.

ssh agent@ opens a persisted chat with the operator's agent —
AGENTBBS_AGENT_CMD runs per message (stdin→stdout), e.g. `claude -p`.

ssh <member>@ with someone else's name prints a classic finger card
(.plan, member since, last seen) and disconnects; your own name still
enters the hub.

cmd/lkpublish: dev publisher for testing (explicit -fps pacing; lksdk
IVF replay mispaces from file timebase alone, measured 1fps from a
15fps file; dimensions required or dynacast pauses the track).

Verified end-to-end against livekit-server --dev: 128k truecolor cells
/ 20k distinct colors streamed over a real SSH session; chat round-trip
and finger card verified over SSH. Go toolchain pinned to 1.26 via
mise.toml (lksdk requirement).

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

internal/store/store.go

@@ -35,6 +35,10 @@ type Store interface {
 	EnsureUser(name, kind, pubkeyFP string) (User, error)
 	// UserByFingerprint finds an account by SSH key fingerprint.
 	UserByFingerprint(fp string) (User, bool, error)
+	// UserByName finds an account by exact username (no creation).
+	UserByName(name string) (User, bool, error)
+	// LastSeen reports the start of the user's most recent session.
+	LastSeen(userID int64) (time.Time, bool, error)
 
 	RecordSession(userID int64, username, remote, route string) (int64, error)
 	EndSession(sessionID int64) error
@@ -46,9 +50,20 @@ type Store interface {
 	PodPaidUntil(userID int64) (time.Time, bool, error)
 	GrantPod(userID int64, until time.Time, paymentRef string) error
 
+	// Chat transcripts for the agent@ surface.
+	AddChat(userID int64, username, role, text string) error
+	RecentChats(username string, n int) ([]ChatMessage, error)
+
 	Close() error
 }
 
+// ChatMessage is one line of an agent@ conversation.
+type ChatMessage struct {
+	Role string // "user" or "agent"
+	Text string
+	At   time.Time
+}
+
 // ErrKeyMismatch means a username is already registered with another key.
 var ErrKeyMismatch = errors.New("username registered with a different key")
 
@@ -92,6 +107,15 @@ CREATE TABLE IF NOT EXISTS scores (
   created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ','now'))
 );
 CREATE INDEX IF NOT EXISTS idx_scores_game ON scores(game, score DESC);
+CREATE TABLE IF NOT EXISTS chat_messages (
+  id INTEGER PRIMARY KEY,
+  user_id INTEGER,
+  username TEXT NOT NULL,
+  role TEXT NOT NULL,
+  text TEXT NOT NULL,
+  created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ','now'))
+);
+CREATE INDEX IF NOT EXISTS idx_chat_user ON chat_messages(username, id);
 CREATE TABLE IF NOT EXISTS pod_subscriptions (
   user_id INTEGER PRIMARY KEY REFERENCES users(id),
   paid_until TEXT NOT NULL,
@@ -211,4 +235,65 @@ func (s *sqliteStore) GrantPod(userID int64, until time.Time, ref string) error
 	return err
 }
 
+func (s *sqliteStore) UserByName(name string) (User, bool, error) {
+	var u User
+	var created string
+	err := s.db.QueryRow(`SELECT id, name, kind, pubkey_fp, created_at FROM users WHERE name = ?`, name).
+		Scan(&u.ID, &u.Name, &u.Kind, &u.PubKeyFP, &created)
+	if err == sql.ErrNoRows {
+		return User{}, false, nil
+	}
+	if err != nil {
+		return User{}, false, err
+	}
+	u.CreatedAt, _ = time.Parse(time.RFC3339, created)
+	return u, true, nil
+}
+
+func (s *sqliteStore) LastSeen(userID int64) (time.Time, bool, error) {
+	var at string
+	err := s.db.QueryRow(`SELECT started_at FROM sessions WHERE user_id = ? ORDER BY id DESC LIMIT 1`, userID).Scan(&at)
+	if err == sql.ErrNoRows {
+		return time.Time{}, false, nil
+	}
+	if err != nil {
+		return time.Time{}, false, err
+	}
+	t, err := time.Parse(time.RFC3339, at)
+	return t, err == nil, err
+}
+
+func (s *sqliteStore) AddChat(userID int64, username, role, text string) error {
+	var uid any
+	if userID > 0 {
+		uid = userID
+	}
+	_, err := s.db.Exec(`INSERT INTO chat_messages (user_id, username, role, text) VALUES (?,?,?,?)`,
+		uid, username, role, text)
+	return err
+}
+
+func (s *sqliteStore) RecentChats(username string, n int) ([]ChatMessage, error) {
+	rows, err := s.db.Query(`
+		SELECT role, text, created_at FROM (
+		  SELECT id, role, text, created_at FROM chat_messages
+		  WHERE username = ? ORDER BY id DESC LIMIT ?
+		) ORDER BY id ASC`, username, n)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var out []ChatMessage
+	for rows.Next() {
+		var m ChatMessage
+		var at string
+		if err := rows.Scan(&m.Role, &m.Text, &at); err != nil {
+			return nil, err
+		}
+		m.At, _ = time.Parse(time.RFC3339, at)
+		out = append(out, m)
+	}
+	return out, rows.Err()
+}
+
 func (s *sqliteStore) Close() error { return s.db.Close() }