feat(minio): initial stable release v1.0.0 — Client interface, xerrors, GetObject, doc examples

Add Client interface with PutObject, GetObject, RemoveObject, PresignedGetObject, and
HandleError; Component now embeds Client with Native() as escape hatch for operations
not covered by the interface. Add xerrors dependency: HandleError maps minio-go error
codes to portable typed codes (NoSuchKey → ErrNotFound, AccessDenied →
ErrPermissionDenied, BucketAlreadyExists → ErrAlreadyExists, etc.). OnStop sets
c.mc = nil for lifecycle consistency. doc.go updated with launcher wiring, upload,
presigned URL, GetObject, and HandleError usage examples. API committed as stable.

What's included:
- Config with Endpoint, AccessKey, SecretKey, UseSSL, Bucket, Region (env-driven, embeddable)
- Transport field in Config for test injection (env:"-", nil uses minio-go default)
- Client interface: PutObject, GetObject, RemoveObject, PresignedGetObject, HandleError
- Component interface: launcher.Component + health.Checkable + Client + Native()
- New(logger, cfg) constructor for lifecycle registration via lc.Append
- Automatic bucket creation on OnStart if bucket does not exist
- Health check via BucketExists at LevelCritical priority
- HandleError: maps minio-go ErrorResponse codes to xerrors typed errors
- 21 unit tests using mock HTTP transport; no live server required

errors_test.go

@@ -0,0 +1,55 @@
+package minio
+
+import (
+	"errors"
+	"testing"
+
+	miniogo "github.com/minio/minio-go/v7"
+
+	"code.nochebuena.dev/go/xerrors"
+)
+
+func assertXCode(t *testing.T, err error, want xerrors.Code) {
+	t.Helper()
+	var xe *xerrors.Err
+	if !errors.As(err, &xe) {
+		t.Fatalf("expected *xerrors.Err, got %T: %v", err, err)
+	}
+	if xe.Code() != want {
+		t.Errorf("want code %s, got %s", want, xe.Code())
+	}
+}
+
+func TestHandleError_Nil(t *testing.T) {
+	if HandleError(nil) != nil {
+		t.Error("HandleError(nil) should return nil")
+	}
+}
+
+func TestHandleError_NoSuchBucket(t *testing.T) {
+	assertXCode(t, HandleError(miniogo.ErrorResponse{Code: miniogo.NoSuchBucket}), xerrors.ErrNotFound)
+}
+
+func TestHandleError_NoSuchKey(t *testing.T) {
+	assertXCode(t, HandleError(miniogo.ErrorResponse{Code: miniogo.NoSuchKey}), xerrors.ErrNotFound)
+}
+
+func TestHandleError_AccessDenied(t *testing.T) {
+	assertXCode(t, HandleError(miniogo.ErrorResponse{Code: miniogo.AccessDenied}), xerrors.ErrPermissionDenied)
+}
+
+func TestHandleError_InvalidAccessKeyID(t *testing.T) {
+	assertXCode(t, HandleError(miniogo.ErrorResponse{Code: miniogo.InvalidAccessKeyID}), xerrors.ErrPermissionDenied)
+}
+
+func TestHandleError_BucketAlreadyExists(t *testing.T) {
+	assertXCode(t, HandleError(miniogo.ErrorResponse{Code: miniogo.BucketAlreadyExists}), xerrors.ErrAlreadyExists)
+}
+
+func TestHandleError_BucketAlreadyOwnedByYou(t *testing.T) {
+	assertXCode(t, HandleError(miniogo.ErrorResponse{Code: miniogo.BucketAlreadyOwnedByYou}), xerrors.ErrAlreadyExists)
+}
+
+func TestHandleError_Unknown(t *testing.T) {
+	assertXCode(t, HandleError(miniogo.ErrorResponse{Code: "SomeUnknownCode"}), xerrors.ErrInternal)
+}