Refactor logging levels and enhance debug messages across multiple components (#1142)

- Changed log level from WARN to DEBUG for session-related messages in hidrpc.go to reduce noise during expected conditions.
- Adjusted logging in nmlite/interface.go to use DEBUG for non-critical DHCP lease messages and router solicitation failures.
- Improved link manager logging in nmlite/link/manager.go to differentiate between expected and persistent interface down states.
- Enhanced DHCP client logging in udhcpc/udhcpc.go to indicate non-fatal errors when calculating lease expiry.

hidrpc.go

@@ -189,12 +189,13 @@ func handleHidRPCKeyboardInput(message hidrpc.Message) error {
 
 func reportHidRPC(params any, session *Session) {
 	if session == nil {
-		logger.Warn().Msg("session is nil, skipping reportHidRPC")
+		logger.Debug().Msg("session is nil, skipping reportHidRPC")
 		return
 	}
 
 	if !session.hidRPCAvailable || session.HidChannel == nil {
-		logger.Warn().
+		// Expected during WebRTC handshake before HID channel is ready
+		logger.Debug().
 			Bool("hidRPCAvailable", session.hidRPCAvailable).
 			Bool("HidChannel", session.HidChannel != nil).
 			Msg("HID RPC is not available, skipping reportHidRPC")

pkg/nmlite/link/manager.go

@@ -197,7 +197,13 @@ func (nm *NetlinkManager) EnsureInterfaceUpWithTimeout(ctx context.Context, ifac
 			l.Info().Msg("interface is up")
 			return link, nil
 		}
-		l.Warn().Msg("interface is still down, retrying")
+		// Use Info for first 5 attempts (expected during boot while PHY negotiates),
+		// then Warn for persistent failures
+		if attempt < 5 {
+			l.Info().Msg("waiting for interface to come up")
+		} else {
+			l.Warn().Msg("interface is still down, retrying")
+		}
 
 		select {
 		case <-time.After(500 * time.Millisecond):

pkg/nmlite/udhcpc/udhcpc.go

@@ -179,7 +179,8 @@ func (c *DHCPClient) loadLeaseFile() error {
 
 	leaseExpiry, err := lease.SetLeaseExpiry()
 	if err != nil {
-		c.logger.Error().Err(err).Msg("failed to get dhcp lease expiry")
+		// Non-fatal: lease still works, we just can't calculate expiry time
+		c.logger.Debug().Err(err).Msg("could not calculate dhcp lease expiry")
 	} else {
 		expiresIn := time.Until(leaseExpiry)
 		c.logger.Info().