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>

docs/scratchpads/fleet-standup-fixes.md

@@ -11,14 +11,14 @@
 ## FIX 2 — socket default trap (absent ⇒ literal default socket, no -L everywhere)
 
 - THE TRAP (3 sites): parseRosterText fallback was DEFAULT_SOCKET_NAME; systemd unit had
-  `Environment=MOSAIC_TMUX_SOCKET=mosaic-factory` + `ExecStop ${…:-mosaic-factory}`; start-agent-session
-  defaulted `:-mosaic-factory`. All fixed → absent socket = '' = default tmux socket (no -L).
+  `Environment=MOSAIC_TMUX_SOCKET=mosaic-fleet` + `ExecStop ${…:-mosaic-fleet}`; start-agent-session
+  defaulted `:-mosaic-fleet`. All fixed → absent socket = '' = default tmux socket (no -L).
 - `socketArgs(name)` helper → `name ? ['-L', name] : []`; replaced all ~15 -L render sites in fleet.ts.
 - shellEnvValue('') now emits a **bare** `VAR=` (not `''`) — unambiguous empty in systemd EnvironmentFile
   (a quoted '' could become a literal socket named "''").
 - start-agent-session.sh: `_tmux` wrapper passes -L only when socket set; mosaic-agent@.service: dropped the
   socket default + conditional ExecStop. So spawn == observe == onboarding cheat-sheet.
-- CONTAINMENT: all 6 shipped presets set socket_name: mosaic-factory explicitly → unaffected; only
+- CONTAINMENT: all 6 shipped presets set socket_name: mosaic-fleet explicitly → unaffected; only
   socket-less rosters (the PoC) get default-socket behavior. DEFAULT_SOCKET_NAME exported for explicit use.
 
 ## Verification