[client] Move ICE and relay workers into the worker package

Relocate WorkerICE (renamed worker.ICE) and WorkerRelay plus ConnPriority
into client/internal/peer/worker. To break the peer<->worker cycle the
workers no longer take *Conn or ConnConfig: callbacks are passed as plain
functions (Conn's unexported methods as method values), and each worker
receives only the fields it needs (key, ICE config, isController) plus a
small services struct. Context is passed to OnNewOffer instead of stored.

Move the worker connection-status helper the other way, out of the worker
package into peer as worker_status.go (WorkerStatus / AtomicWorkerStatus),
since only Conn uses it.

client/internal/peer/event.go

@@ -6,6 +6,7 @@ import (
 	"github.com/pion/ice/v4"
 
 	"github.com/netbirdio/netbird/client/internal/peer/signaling"
+	"github.com/netbirdio/netbird/client/internal/peer/worker"
 	"github.com/netbirdio/netbird/route"
 )
 
@@ -35,8 +36,8 @@ type evRemoteCandidate struct {
 }
 
 type evICEReady struct {
-	priority ConnPriority
-	info     ICEConnInfo
+	priority worker.ConnPriority
+	info     worker.ICEConnInfo
 }
 
 type evICEDown struct {
@@ -44,7 +45,7 @@ type evICEDown struct {
 }
 
 type evRelayReady struct {
-	info RelayConnInfo
+	info worker.RelayConnInfo
 }
 
 type evRelayDown struct{}