feat(config): add MinIO object storage configuration

Add MinioConfig struct with connection, bucket, chunk size, and session TTL settings.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

internal/config/config_test.go

@@ -254,3 +254,135 @@ log:
 		t.Errorf("Log.FilePath = %q, want %q", cfg.Log.FilePath, "/var/log/app.log")
 	}
 }
+
+func TestLoadWithMinioConfig(t *testing.T) {
+	content := []byte(`server_port: "9090"
+slurm_api_url: "http://slurm.example.com:6820"
+slurm_user_name: "admin"
+slurm_jwt_key_path: "/etc/slurm/jwt.key"
+mysql_dsn: "user:pass@tcp(10.0.0.1:3306)/testdb?parseTime=true"
+minio:
+  endpoint: "minio.example.com:9000"
+  access_key: "myaccesskey"
+  secret_key: "mysecretkey"
+  bucket: "test-bucket"
+  use_ssl: true
+  chunk_size: 33554432
+  max_file_size: 107374182400
+  min_chunk_size: 10485760
+  session_ttl: 24
+`)
+
+	dir := t.TempDir()
+	path := filepath.Join(dir, "config.yaml")
+	if err := os.WriteFile(path, content, 0644); err != nil {
+		t.Fatalf("write temp config: %v", err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+
+	if cfg.Minio.Endpoint != "minio.example.com:9000" {
+		t.Errorf("Minio.Endpoint = %q, want %q", cfg.Minio.Endpoint, "minio.example.com:9000")
+	}
+	if cfg.Minio.AccessKey != "myaccesskey" {
+		t.Errorf("Minio.AccessKey = %q, want %q", cfg.Minio.AccessKey, "myaccesskey")
+	}
+	if cfg.Minio.SecretKey != "mysecretkey" {
+		t.Errorf("Minio.SecretKey = %q, want %q", cfg.Minio.SecretKey, "mysecretkey")
+	}
+	if cfg.Minio.Bucket != "test-bucket" {
+		t.Errorf("Minio.Bucket = %q, want %q", cfg.Minio.Bucket, "test-bucket")
+	}
+	if cfg.Minio.UseSSL != true {
+		t.Errorf("Minio.UseSSL = %v, want %v", cfg.Minio.UseSSL, true)
+	}
+	if cfg.Minio.ChunkSize != 33554432 {
+		t.Errorf("Minio.ChunkSize = %d, want %d", cfg.Minio.ChunkSize, 33554432)
+	}
+	if cfg.Minio.MaxFileSize != 107374182400 {
+		t.Errorf("Minio.MaxFileSize = %d, want %d", cfg.Minio.MaxFileSize, 107374182400)
+	}
+	if cfg.Minio.MinChunkSize != 10485760 {
+		t.Errorf("Minio.MinChunkSize = %d, want %d", cfg.Minio.MinChunkSize, 10485760)
+	}
+	if cfg.Minio.SessionTTL != 24 {
+		t.Errorf("Minio.SessionTTL = %d, want %d", cfg.Minio.SessionTTL, 24)
+	}
+}
+
+func TestLoadWithoutMinioConfig(t *testing.T) {
+	content := []byte(`server_port: "8080"
+slurm_api_url: "http://localhost:6820"
+slurm_user_name: "root"
+slurm_jwt_key_path: "/etc/slurm/jwt_hs256.key"
+mysql_dsn: "root:@tcp(127.0.0.1:3306)/hpc_platform?parseTime=true"
+`)
+
+	dir := t.TempDir()
+	path := filepath.Join(dir, "config.yaml")
+	if err := os.WriteFile(path, content, 0644); err != nil {
+		t.Fatalf("write temp config: %v", err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+
+	if cfg.Minio.Endpoint != "" {
+		t.Errorf("Minio.Endpoint = %q, want empty string", cfg.Minio.Endpoint)
+	}
+	if cfg.Minio.AccessKey != "" {
+		t.Errorf("Minio.AccessKey = %q, want empty string", cfg.Minio.AccessKey)
+	}
+	if cfg.Minio.SecretKey != "" {
+		t.Errorf("Minio.SecretKey = %q, want empty string", cfg.Minio.SecretKey)
+	}
+	if cfg.Minio.Bucket != "" {
+		t.Errorf("Minio.Bucket = %q, want empty string", cfg.Minio.Bucket)
+	}
+	if cfg.Minio.UseSSL != false {
+		t.Errorf("Minio.UseSSL = %v, want false", cfg.Minio.UseSSL)
+	}
+}
+
+func TestLoadMinioDefaults(t *testing.T) {
+	content := []byte(`server_port: "8080"
+slurm_api_url: "http://localhost:6820"
+slurm_user_name: "root"
+slurm_jwt_key_path: "/etc/slurm/jwt_hs256.key"
+mysql_dsn: "root:@tcp(127.0.0.1:3306)/hpc_platform?parseTime=true"
+minio:
+  endpoint: "localhost:9000"
+  access_key: "minioadmin"
+  secret_key: "minioadmin"
+  bucket: "uploads"
+`)
+
+	dir := t.TempDir()
+	path := filepath.Join(dir, "config.yaml")
+	if err := os.WriteFile(path, content, 0644); err != nil {
+		t.Fatalf("write temp config: %v", err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+
+	if cfg.Minio.ChunkSize != 16<<20 {
+		t.Errorf("Minio.ChunkSize = %d, want %d", cfg.Minio.ChunkSize, 16<<20)
+	}
+	if cfg.Minio.MaxFileSize != 50<<30 {
+		t.Errorf("Minio.MaxFileSize = %d, want %d", cfg.Minio.MaxFileSize, 50<<30)
+	}
+	if cfg.Minio.MinChunkSize != 5<<20 {
+		t.Errorf("Minio.MinChunkSize = %d, want %d", cfg.Minio.MinChunkSize, 5<<20)
+	}
+	if cfg.Minio.SessionTTL != 48 {
+		t.Errorf("Minio.SessionTTL = %d, want %d", cfg.Minio.SessionTTL, 48)
+	}
+}