Unify cache polling on CACHE_STATUS and split API docs.

Replace separate accel/tap snapshot UART commands with one clients[] response
that omits unsubscribed fields; remove snapshot handlers and CLI commands.
Add goTool/docs for WebSocket streams and REST; tap-snapshot REST uses CACHE_STATUS.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/cmd_cache_status.go

@@ -9,26 +9,24 @@ func runCacheStatus(sp *serialPort) error {
 	if err != nil {
 		return err
 	}
-	accel := r.GetAccel()
-	if len(accel) == 0 {
-		fmt.Println("accel: (none — no slaves with accel stream enabled)")
-	} else {
-		for _, s := range accel {
-			if !s.GetValid() {
-				fmt.Printf("accel client %d: no sample yet\n", s.GetClientId())
-				continue
-			}
-			fmt.Printf("accel client %d: x=%d y=%d z=%d (age %d ms)\n",
-				s.GetClientId(), s.GetX(), s.GetY(), s.GetZ(), s.GetAgeMs())
-		}
+	clients := r.GetClients()
+	if len(clients) == 0 {
+		fmt.Println("(no slaves with accel stream or tap notify enabled)")
+		return nil
 	}
-	taps := r.GetTaps()
-	if len(taps) == 0 {
-		fmt.Println("tap: (none pending)")
-	} else {
-		for _, e := range taps {
-			fmt.Printf("tap client %d: %s (age %d ms)\n",
-				e.GetClientId(), tapKindLabel(e.GetKind()), e.GetAgeMs())
+	for _, c := range clients {
+		id := c.GetClientId()
+		if a := c.GetAccel(); a != nil {
+			if !a.GetValid() {
+				fmt.Printf("client %d accel: no sample yet\n", id)
+			} else {
+				fmt.Printf("client %d accel: x=%d y=%d z=%d (age %d ms)\n",
+					id, a.GetX(), a.GetY(), a.GetZ(), a.GetAgeMs())
+			}
+		}
+		if t := c.GetTap(); t != nil {
+			fmt.Printf("client %d tap: %s (age %d ms)\n",
+				id, tapKindLabel(t.GetKind()), t.GetAgeMs())
 		}
 	}
 	return nil