refactor(fleet): rename tmux socket mosaic-factory → mosaic-fleet (#630)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

packages/mosaic/framework/tools/fleet/start-agent-session.sh

@@ -3,7 +3,7 @@ set -euo pipefail
 
 AGENT_NAME=${1:-${MOSAIC_AGENT_NAME:-}}
 # Absent socket ⇒ the LITERAL default tmux socket (no -L). The roster's
-# socket_name is honored when set; absent never silently becomes mosaic-factory
+# socket_name is honored when set; absent never silently becomes mosaic-fleet
 # (spawn stays consistent with the onboarding cheat-sheet + fleet ps observe).
 MOSAIC_TMUX_SOCKET=${MOSAIC_TMUX_SOCKET:-}
 MOSAIC_AGENT_RUNTIME=${MOSAIC_AGENT_RUNTIME:-pi}