all: use zstdframe where sensible (#11491)

Use the zstdframe package where sensible instead of plumbing
around our own zstd.Encoder just for stateless operations.

This causes logtail to have a dependency on zstd,
but that's arguably okay since zstd support is implicit
to the protocol between a client and the logging service.
Also, virtually every caller to logger.NewLogger was
manually setting up a zstd.Encoder anyways,
meaning that zstd was functionally always a dependency.

Updates #cleanup
Updates tailscale/corp#18514

Signed-off-by: Joe Tsai <joetsai@digital-static.net>

control/controlclient/direct.go

@@ -42,7 +42,6 @@ import (
 	"tailscale.com/net/tlsdial"
 	"tailscale.com/net/tsdial"
 	"tailscale.com/net/tshttpproxy"
-	"tailscale.com/smallzstd"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tka"
 	"tailscale.com/tstime"
@@ -57,6 +56,7 @@ import (
 	"tailscale.com/util/singleflight"
 	"tailscale.com/util/syspolicy"
 	"tailscale.com/util/systemd"
+	"tailscale.com/util/zstdframe"
 )
 
 // Direct is the client that connects to a tailcontrol server for a node.
@@ -180,11 +180,6 @@ type Pinger interface {
 	Ping(ctx context.Context, ip netip.Addr, pingType tailcfg.PingType, size int) (*ipnstate.PingResult, error)
 }
 
-type Decompressor interface {
-	DecodeAll(input, dst []byte) ([]byte, error)
-	Close()
-}
-
 // NetmapUpdater is the interface needed by the controlclient to enact change in
 // the world as a function of updates received from the network.
 type NetmapUpdater interface {
@@ -1208,12 +1203,7 @@ func (c *Direct) decodeMsg(msg []byte, v any, mkey key.MachinePrivate) error {
 	} else {
 		decrypted = msg
 	}
-	decoder, err := smallzstd.NewDecoder(nil)
-	if err != nil {
-		return err
-	}
-	defer decoder.Close()
-	b, err := decoder.DecodeAll(decrypted, nil)
+	b, err := zstdframe.AppendDecode(nil, decrypted)
 	if err != nil {
 		return err
 	}