feat(devops): add config loading

Loads ~/.core/config.yaml with image source preferences.
Defaults to auto-detection with host-uk/core-images.

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

pkg/devops/config.go

@@ -0,0 +1,86 @@
+package devops
+
+import (
+	"os"
+	"path/filepath"
+
+	"gopkg.in/yaml.v3"
+)
+
+// Config holds global devops configuration from ~/.core/config.yaml.
+type Config struct {
+	Version int          `yaml:"version"`
+	Images  ImagesConfig `yaml:"images"`
+}
+
+// ImagesConfig holds image source configuration.
+type ImagesConfig struct {
+	Source   string         `yaml:"source"` // auto, github, registry, cdn
+	GitHub   GitHubConfig   `yaml:"github,omitempty"`
+	Registry RegistryConfig `yaml:"registry,omitempty"`
+	CDN      CDNConfig      `yaml:"cdn,omitempty"`
+}
+
+// GitHubConfig holds GitHub Releases configuration.
+type GitHubConfig struct {
+	Repo string `yaml:"repo"` // owner/repo format
+}
+
+// RegistryConfig holds container registry configuration.
+type RegistryConfig struct {
+	Image string `yaml:"image"` // e.g., ghcr.io/host-uk/core-devops
+}
+
+// CDNConfig holds CDN/S3 configuration.
+type CDNConfig struct {
+	URL string `yaml:"url"` // base URL for downloads
+}
+
+// DefaultConfig returns sensible defaults.
+func DefaultConfig() *Config {
+	return &Config{
+		Version: 1,
+		Images: ImagesConfig{
+			Source: "auto",
+			GitHub: GitHubConfig{
+				Repo: "host-uk/core-images",
+			},
+			Registry: RegistryConfig{
+				Image: "ghcr.io/host-uk/core-devops",
+			},
+		},
+	}
+}
+
+// ConfigPath returns the path to the config file.
+func ConfigPath() (string, error) {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(home, ".core", "config.yaml"), nil
+}
+
+// LoadConfig loads configuration from ~/.core/config.yaml.
+// Returns default config if file doesn't exist.
+func LoadConfig() (*Config, error) {
+	configPath, err := ConfigPath()
+	if err != nil {
+		return DefaultConfig(), nil
+	}
+
+	data, err := os.ReadFile(configPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return DefaultConfig(), nil
+		}
+		return nil, err
+	}
+
+	cfg := DefaultConfig()
+	if err := yaml.Unmarshal(data, cfg); err != nil {
+		return nil, err
+	}
+
+	return cfg, nil
+}

pkg/devops/config_test.go

@@ -0,0 +1,48 @@
+package devops
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestLoadConfig_Good_Default(t *testing.T) {
+	// Use temp home dir
+	tmpDir := t.TempDir()
+	t.Setenv("HOME", tmpDir)
+
+	cfg, err := LoadConfig()
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if cfg.Images.Source != "auto" {
+		t.Errorf("expected source 'auto', got %q", cfg.Images.Source)
+	}
+}
+
+func TestLoadConfig_Good_FromFile(t *testing.T) {
+	tmpDir := t.TempDir()
+	t.Setenv("HOME", tmpDir)
+
+	configDir := filepath.Join(tmpDir, ".core")
+	os.MkdirAll(configDir, 0755)
+
+	configContent := `version: 1
+images:
+  source: github
+  github:
+    repo: myorg/images
+`
+	os.WriteFile(filepath.Join(configDir, "config.yaml"), []byte(configContent), 0644)
+
+	cfg, err := LoadConfig()
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if cfg.Images.Source != "github" {
+		t.Errorf("expected source 'github', got %q", cfg.Images.Source)
+	}
+	if cfg.Images.GitHub.Repo != "myorg/images" {
+		t.Errorf("expected repo 'myorg/images', got %q", cfg.Images.GitHub.Repo)
+	}
+}

pkg/devops/go.mod

@@ -4,4 +4,6 @@ go 1.25
 
 require github.com/host-uk/core v0.0.0
 
+require gopkg.in/yaml.v3 v3.0.1 // indirect
+
 replace github.com/host-uk/core => ../..

pkg/devops/go.sum

@@ -1,4 +1,6 @@
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=