fix: address CodeRabbit feedback - use errors.E for context

Add contextual error handling using errors.E helper as suggested:
- config.go: Wrap LoadConfig read/parse errors
- images.go: Wrap NewImageManager, loadManifest, and Manifest.Save errors

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

pkg/devops/config.go

@@ -4,6 +4,7 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/host-uk/core/pkg/errors"
 	"github.com/host-uk/core/pkg/io"
 	"gopkg.in/yaml.v3"
 )
@@ -75,12 +76,12 @@ func LoadConfig() (*Config, error) {
 		if os.IsNotExist(err) {
 			return DefaultConfig(), nil
 		}
-		return nil, err
+		return nil, errors.E("devops.LoadConfig", "failed to read config", err)
 	}
 
 	cfg := DefaultConfig()
 	if err := yaml.Unmarshal([]byte(content), cfg); err != nil {
-		return nil, err
+		return nil, errors.E("devops.LoadConfig", "failed to parse config", err)
 	}
 
 	return cfg, nil

pkg/devops/images.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/host-uk/core/pkg/devops/sources"
+	"github.com/host-uk/core/pkg/errors"
 	"github.com/host-uk/core/pkg/io"
 )
 
@@ -42,7 +43,7 @@ func NewImageManager(cfg *Config) (*ImageManager, error) {
 
 	// Ensure images directory exists
 	if err := io.Local.EnsureDir(imagesDir); err != nil {
-		return nil, err
+		return nil, errors.E("devops.NewImageManager", "failed to create images directory", err)
 	}
 
 	// Load or create manifest
@@ -172,11 +173,11 @@ func loadManifest(path string) (*Manifest, error) {
 		if os.IsNotExist(err) {
 			return m, nil
 		}
-		return nil, err
+		return nil, errors.E("devops.loadManifest", "failed to read manifest", err)
 	}
 
 	if err := json.Unmarshal([]byte(content), m); err != nil {
-		return nil, err
+		return nil, errors.E("devops.loadManifest", "failed to parse manifest", err)
 	}
 	m.path = path
 
@@ -187,7 +188,10 @@ func loadManifest(path string) (*Manifest, error) {
 func (m *Manifest) Save() error {
 	data, err := json.MarshalIndent(m, "", "  ")
 	if err != nil {
-		return err
+		return errors.E("devops.Manifest.Save", "failed to marshal manifest", err)
 	}
-	return io.Local.Write(m.path, string(data))
+	if err := io.Local.Write(m.path, string(data)); err != nil {
+		return errors.E("devops.Manifest.Save", "failed to write manifest", err)
+	}
+	return nil
 }