feat(release): migrate filesystem operations to io.Local abstraction

Migrate config.go:
- os.ReadFile → io.Local.Read
- os.Stat → io.Local.IsFile
- os.MkdirAll → io.Local.EnsureDir
- os.WriteFile → io.Local.Write

Migrate release.go:
- os.Stat → io.Local.IsDir
- os.ReadDir → io.Local.List

Uses filepath.Abs for relative path support.

Part of #101 (io.Medium migration tracking issue).

Closes #106

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

pkg/release/config.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/host-uk/core/pkg/io"
 	"gopkg.in/yaml.v3"
 )
 
@@ -171,7 +172,13 @@ type ChangelogConfig struct {
 func LoadConfig(dir string) (*Config, error) {
 	configPath := filepath.Join(dir, ConfigDir, ConfigFileName)
 
-	data, err := os.ReadFile(configPath)
+	// Convert to absolute path for io.Local
+	absPath, err := filepath.Abs(configPath)
+	if err != nil {
+		return nil, fmt.Errorf("release.LoadConfig: failed to resolve path: %w", err)
+	}
+
+	content, err := io.Local.Read(absPath)
 	if err != nil {
 		if os.IsNotExist(err) {
 			cfg := DefaultConfig()
@@ -182,7 +189,7 @@ func LoadConfig(dir string) (*Config, error) {
 	}
 
 	var cfg Config
-	if err := yaml.Unmarshal(data, &cfg); err != nil {
+	if err := yaml.Unmarshal([]byte(content), &cfg); err != nil {
 		return nil, fmt.Errorf("release.LoadConfig: failed to parse config file: %w", err)
 	}
 
@@ -263,8 +270,12 @@ func ConfigPath(dir string) string {
 
 // ConfigExists checks if a release config file exists in the given directory.
 func ConfigExists(dir string) bool {
-	_, err := os.Stat(ConfigPath(dir))
-	return err == nil
+	configPath := ConfigPath(dir)
+	absPath, err := filepath.Abs(configPath)
+	if err != nil {
+		return false
+	}
+	return io.Local.IsFile(absPath)
 }
 
 // GetRepository returns the repository from the config.
@@ -281,9 +292,15 @@ func (c *Config) GetProjectName() string {
 func WriteConfig(cfg *Config, dir string) error {
 	configPath := ConfigPath(dir)
 
+	// Convert to absolute path for io.Local
+	absPath, err := filepath.Abs(configPath)
+	if err != nil {
+		return fmt.Errorf("release.WriteConfig: failed to resolve path: %w", err)
+	}
+
 	// Ensure directory exists
-	configDir := filepath.Dir(configPath)
-	if err := os.MkdirAll(configDir, 0755); err != nil {
+	configDir := filepath.Dir(absPath)
+	if err := io.Local.EnsureDir(configDir); err != nil {
 		return fmt.Errorf("release.WriteConfig: failed to create directory: %w", err)
 	}
 
@@ -292,7 +309,7 @@ func WriteConfig(cfg *Config, dir string) error {
 		return fmt.Errorf("release.WriteConfig: failed to marshal config: %w", err)
 	}
 
-	if err := os.WriteFile(configPath, data, 0644); err != nil {
+	if err := io.Local.Write(absPath, string(data)); err != nil {
 		return fmt.Errorf("release.WriteConfig: failed to write config file: %w", err)
 	}
 

pkg/release/release.go

@@ -6,12 +6,12 @@ package release
 import (
 	"context"
 	"fmt"
-	"os"
 	"path/filepath"
 	"strings"
 
 	"github.com/host-uk/core/pkg/build"
 	"github.com/host-uk/core/pkg/build/builders"
+	"github.com/host-uk/core/pkg/io"
 	"github.com/host-uk/core/pkg/release/publishers"
 )
 
@@ -103,13 +103,13 @@ func Publish(ctx context.Context, cfg *Config, dryRun bool) (*Release, error) {
 
 // findArtifacts discovers pre-built artifacts in the dist directory.
 func findArtifacts(distDir string) ([]build.Artifact, error) {
-	if _, err := os.Stat(distDir); os.IsNotExist(err) {
+	if !io.Local.IsDir(distDir) {
 		return nil, fmt.Errorf("dist/ directory not found")
 	}
 
 	var artifacts []build.Artifact
 
-	entries, err := os.ReadDir(distDir)
+	entries, err := io.Local.List(distDir)
 	if err != nil {
 		return nil, fmt.Errorf("failed to read dist/: %w", err)
 	}