feat(storage-minio): initial implementation — MinIO/S3 object storage with lifecycle (v1.0.0)

Introduces code.nochebuena.dev/einherjar/storage-minio — the object storage
starter for the Einherjar framework. Absorbs the minio package from micro-lib,
replacing fmt.Errorf wrapping with core/xerrors.

Interfaces (CT-6: one TypeSpec per file):
- Provider — PutObject, RemoveObject, GetObject, PresignedGetObject, HandleError
- Component — lifecycle.Component + observability.Checkable + Provider + Native()

Implementation:
- New(logger, cfg) Component — client not created until OnInit
- OnInit: minio.New with credentials and transport; bucket existence check
- OnStart: BucketExists PING; logs "minio: connected"
- OnStop: logs "minio: closing client" (minio-go is stateless; no explicit close)
- HealthCheck: BucketExists check; Priority LevelCritical
- Native() *miniogo.Client — escape hatch for operations not in Provider
- HandleError: maps minio-go errors to xerrors (NotFound, AlreadyExists, Internal)

Config (EINHERJAR_MINIO_* env vars):
  Endpoint(required), AccessKey(required), SecretKey(required),
  Bucket(required), UseSSL(false), Region(us-east-1)

- Component interface embeds observability.Identifiable; identifiable.go implements
  ModulePath and ModuleVersion via runtime/debug.ReadBuildInfo() — prints in launcher banner

config.go

@@ -0,0 +1,27 @@
+package minio
+
+import "net/http"
+
+// Config holds MinIO connection settings. Required fields must be supplied
+// by the caller; optional fields have production-safe defaults via DefaultConfig.
+type Config struct {
+	Endpoint  string `env:"EINHERJAR_MINIO_ENDPOINT,required"`
+	AccessKey string `env:"EINHERJAR_MINIO_ACCESS_KEY,required"`
+	SecretKey string `env:"EINHERJAR_MINIO_SECRET_KEY,required"`
+	UseSSL    bool   `env:"EINHERJAR_MINIO_USE_SSL"     envDefault:"false"`
+	Bucket    string `env:"EINHERJAR_MINIO_BUCKET,required"`
+	// Region defaults to "us-east-1" — the region MinIO uses by default on self-hosted
+	// deployments. Setting a non-empty region bypasses per-request region detection.
+	Region string `env:"EINHERJAR_MINIO_REGION" envDefault:"us-east-1"`
+	// Transport is used for testing only. Nil uses the minio-go default transport.
+	Transport http.RoundTripper `env:"-"`
+}
+
+// DefaultConfig returns a Config with all optional fields set to production-safe
+// defaults. Callers must supply Endpoint, AccessKey, SecretKey, and Bucket.
+func DefaultConfig() Config {
+	return Config{
+		UseSSL: false,
+		Region: "us-east-1",
+	}
+}