Add deadlines to git network ops and lock merges per project

internal/agents/manager.go

@@ -59,8 +59,8 @@ type Manager struct {
 	snapMu sync.Mutex
 	snaps  map[string]*snapState
 
-	mergeMu      sync.Mutex
-	mergeHolders map[string]string
+	mergeMu sync.Mutex
+	merges  map[string]*projectMerge
 
 	reviewMu sync.Mutex
 
@@ -130,7 +130,7 @@ func New(st *store.Store, worktreeRoot, leadRoot, codexHome string) *Manager {
 		finishing:    map[string]bool{},
 		signals:      make(chan []api.Event, 1024),
 		snaps:        map[string]*snapState{},
-		mergeHolders: map[string]string{},
+		merges:       map[string]*projectMerge{},
 		bad:          newBadLines(),
 		watchStop:    make(chan struct{}),
 	}