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/jackc/puddle/v2/nanotime.go

@@ -0,0 +1,16 @@
+package puddle
+
+import "time"
+
+// nanotime returns the time in nanoseconds since process start.
+//
+// This approach, described at
+// https://github.com/golang/go/issues/61765#issuecomment-1672090302,
+// is fast, monotonic, and portable, and avoids the previous
+// dependence on runtime.nanotime using the (unsafe) linkname hack.
+// In particular, time.Since does less work than time.Now.
+func nanotime() int64 {
+	return time.Since(globalStart).Nanoseconds()
+}
+
+var globalStart = time.Now()