aider/observer: improve logging

Signed-off-by: Jakub Sztandera <oss@kubuxu.com>

Author: Kubuxu

observer/model.go

@@ -151,11 +151,11 @@ func supplementalDataFromGpbft(sd gpbft.SupplementalData) SupplementalData {
 func (m Message) ToPartialMessage() (*gpbft.PartialGMessage, error) {
 	payload, err := m.Vote.ToGpbftPayload()
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("could not convert vote to gpbft payload: %w", err)
 	}
 	gj, err := m.Justification.ToGpbftJustification()
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("could not convert justification to gpbft justification: %w", err)
 	}
 
 	return &gpbft.PartialGMessage{
@@ -173,16 +173,16 @@ func (m Message) ToPartialMessage() (*gpbft.PartialGMessage, error) {
 func (p Payload) ToGpbftPayload() (gpbft.Payload, error) {
 	phase, err := phaseFromString(p.Phase)
 	if err != nil {
-		return gpbft.Payload{}, err
+		return gpbft.Payload{}, fmt.Errorf("could not convert phase: %w", err)
 	}
 	sd, err := p.SupplementalData.ToGpbftSupplementalData()
 	if err != nil {
-		return gpbft.Payload{}, err
+		return gpbft.Payload{}, fmt.Errorf("could not convert supplemental data: %w", err)
 	}
 
 	gv, err := ToGpbftChain(p.Value...)
 	if err != nil {
-		return gpbft.Payload{}, err
+		return gpbft.Payload{}, fmt.Errorf("could not convert value: %w", err)
 	}
 
 	return gpbft.Payload{
@@ -246,14 +246,14 @@ func (j *Justification) ToGpbftJustification() (*gpbft.Justification, error) {
 	gsigners, _ := bitfield.NewFromIter(ri)
 	payload, err := j.Vote.ToGpbftPayload()
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("could not convert vote to gpbft payload: %w", err)
 	}
 
 	// Embedded struct as json, hence the decode.
 	s := string(j.Signature)
 	decoded, err := base64.StdEncoding.DecodeString(s)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("could not decode signature: %w", err)
 	}
 
 	return &gpbft.Justification{