feat(bun): generate native Go array slices for PostgreSQL array columns

Bun's pgdialect scans/appends native slices directly, so array columns
(text[], integer[], uuid[], ...) always generate as plain []string,
[]int32, etc. with an explicit "array" bun tag, regardless of --types
(sqltypes/stdlib/baselib). The SqlXxxArray wrapper types are no longer
used for Bun array columns (gorm is unaffected and keeps using them).

Adds --array-nullable pointer_slice to represent nullable array columns
as *[]T instead of []T, so callers can distinguish SQL NULL (nil) from
'{}' (pointer to an empty slice). Verified end-to-end against a live
PostgreSQL instance for NULL/{}/populated arrays in every --types mode.

Closes #13

vendor/github.com/uptrace/bun/dialect/pgdialect/hstore.go

@@ -0,0 +1,73 @@
+package pgdialect
+
+import (
+	"database/sql"
+	"fmt"
+	"reflect"
+
+	"github.com/uptrace/bun/schema"
+)
+
+type HStoreValue struct {
+	v reflect.Value
+
+	append schema.AppenderFunc
+	scan   schema.ScannerFunc
+}
+
+// HStore accepts a map[string]string and returns a wrapper for working with PostgreSQL
+// hstore data type.
+//
+// For struct fields you can use hstore tag:
+//
+//	Attrs  map[string]string `bun:",hstore"`
+func HStore(vi any) *HStoreValue {
+	v := reflect.ValueOf(vi)
+	if !v.IsValid() {
+		panic(fmt.Errorf("bun: HStore(nil)"))
+	}
+
+	typ := v.Type()
+	if typ.Kind() == reflect.Ptr {
+		typ = typ.Elem()
+	}
+	if typ.Kind() != reflect.Map {
+		panic(fmt.Errorf("bun: Hstore(unsupported %s)", typ))
+	}
+
+	return &HStoreValue{
+		v: v,
+
+		append: pgDialect.hstoreAppender(v.Type()),
+		scan:   hstoreScanner(v.Type()),
+	}
+}
+
+var (
+	_ schema.QueryAppender = (*HStoreValue)(nil)
+	_ sql.Scanner          = (*HStoreValue)(nil)
+)
+
+func (h *HStoreValue) AppendQuery(gen schema.QueryGen, b []byte) ([]byte, error) {
+	if h.append == nil {
+		panic(fmt.Errorf("bun: HStore(unsupported %s)", h.v.Type()))
+	}
+	return h.append(gen, b, h.v), nil
+}
+
+func (h *HStoreValue) Scan(src any) error {
+	if h.scan == nil {
+		return fmt.Errorf("bun: HStore(unsupported %s)", h.v.Type())
+	}
+	if h.v.Kind() != reflect.Ptr {
+		return fmt.Errorf("bun: HStore(non-pointer %s)", h.v.Type())
+	}
+	return h.scan(h.v.Elem(), src)
+}
+
+func (h *HStoreValue) Value() any {
+	if h.v.IsValid() {
+		return h.v.Interface()
+	}
+	return nil
+}