chore: rename Coordinator to CoordinatorV1 (#11222)

Renames the tailnet.Coordinator to represent both v1 and v2 APIs, so that we can use this interface for the main atomic pointer.

Part of #10532

tailnet/coordinator.go

@@ -27,6 +27,11 @@ import (
 // └──────────────────┘   └────────────────────┘   └───────────────────┘   └──────────────────┘
 // Coordinators have different guarantees for HA support.
 type Coordinator interface {
+	CoordinatorV1
+	CoordinatorV2
+}
+
+type CoordinatorV1 interface {
 	// ServeHTTPDebug serves a debug webpage that shows the internal state of
 	// the coordinator.
 	ServeHTTPDebug(w http.ResponseWriter, r *http.Request)
@@ -143,16 +148,6 @@ func NewCoordinator(logger slog.Logger) Coordinator {
 	}
 }
 
-// NewCoordinatorV2 constructs a new in-memory connection coordinator. This
-// coordinator is incompatible with multiple Coder replicas as all node data is
-// in-memory.
-func NewCoordinatorV2(logger slog.Logger) CoordinatorV2 {
-	return &coordinator{
-		core:       newCore(logger.Named(LoggerName)),
-		closedChan: make(chan struct{}),
-	}
-}
-
 // coordinator exchanges nodes with agents to establish connections entirely in-memory.
 // The Enterprise implementation provides this for high-availability.
 // ┌──────────────────┐   ┌────────────────────┐   ┌───────────────────┐   ┌──────────────────┐