fix(writers): drop version stamps from generated output

Generated files carried the RelSpec version and build date, so every
rebuild produced a diff even when the schema was unchanged.

- bun, gorm, drizzle: remove the GeneratedBy template field and line
- pgsql, mssql, sqlite: emit a constant "-- Generated by RelSpec"
- bun: replace the version header test with a version-free assertion

pkg/buildinfo is unchanged and still backs the CLI version.

pkg/writers/bun/template_data.go

@@ -6,7 +6,6 @@ import (
 	"sort"
 	"strings"
 
-	"git.warky.dev/wdevs/relspecgo/pkg/buildinfo"
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
 	"git.warky.dev/wdevs/relspecgo/pkg/writers"
 )
@@ -14,7 +13,6 @@ import (
 // TemplateData represents the data passed to the template for code generation
 type TemplateData struct {
 	PackageName string
-	GeneratedBy string
 	Imports     []string
 	Models      []*ModelData
 	Config      *MethodConfig
@@ -167,7 +165,6 @@ func NewTemplateData(packageName string, config *MethodConfig) *TemplateData {
 
 	return &TemplateData{
 		PackageName: packageName,
-		GeneratedBy: buildinfo.GeneratedComment(),
 		Imports:     make([]string, 0),
 		Models:      make([]*ModelData, 0),
 		Config:      config,

pkg/writers/bun/templates.go

@@ -7,8 +7,7 @@ import (
 
 // modelTemplate defines the template for generating Bun models
 const modelTemplate = `// Code generated by relspecgo. DO NOT EDIT.
-{{if .GeneratedBy}}// {{.GeneratedBy}}
-{{end}}package {{.PackageName}}
+package {{.PackageName}}
 
 {{if .Imports -}}
 import (

pkg/writers/bun/writer_test.go

@@ -8,7 +8,6 @@ import (
 	"strings"
 	"testing"
 
-	"git.warky.dev/wdevs/relspecgo/pkg/buildinfo"
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
 	"git.warky.dev/wdevs/relspecgo/pkg/writers"
 )
@@ -121,7 +120,7 @@ func TestWriter_WriteTable_MultilineDescriptionProducesValidGo(t *testing.T) {
 	}
 }
 
-func TestWriter_WriteTable_EmbedsRelspecVersionHeader(t *testing.T) {
+func TestWriter_WriteTable_HeaderIsVersionFree(t *testing.T) {
 	table := models.InitTable("users", "public")
 	table.Columns["id"] = &models.Column{Name: "id", Type: "bigint", IsPrimaryKey: true, NotNull: true, Sequence: 1}
 
@@ -141,19 +140,14 @@ func TestWriter_WriteTable_EmbedsRelspecVersionHeader(t *testing.T) {
 		t.Fatalf("generated code is invalid Go: %v\n%s", err, src)
 	}
 
-	wantHeader := "// " + buildinfo.GeneratedComment()
-	if !strings.Contains(src, wantHeader) {
-		t.Errorf("generated code missing RelSpec version header %q\n%s", wantHeader, src)
+	// Output must be reproducible: no version or build date in the header.
+	if strings.Contains(src, "(built: ") || strings.Contains(src, "RelSpec ") {
+		t.Errorf("generated code still carries a version header\n%s", src)
 	}
-	// The provenance comment must sit between the "Code generated" marker and the package clause.
-	genIdx := strings.Index(src, "// Code generated by relspecgo. DO NOT EDIT.")
-	hdrIdx := strings.Index(src, wantHeader)
-	pkgIdx := strings.Index(src, "package models")
-	if genIdx < 0 || hdrIdx < 0 || pkgIdx < 0 || !(genIdx < hdrIdx && hdrIdx < pkgIdx) {
-		t.Errorf("RelSpec version header is misplaced (gen=%d hdr=%d pkg=%d)\n%s", genIdx, hdrIdx, pkgIdx, src)
-	}
-	if !strings.Contains(wantHeader, "RelSpec ") || !strings.Contains(wantHeader, "(built: ") {
-		t.Errorf("version header not in expected 'RelSpec <version> (built: <date>)' form: %q", wantHeader)
+	// The "Code generated" marker must sit directly above the package clause.
+	want := "// Code generated by relspecgo. DO NOT EDIT.\npackage models"
+	if !strings.Contains(src, want) {
+		t.Errorf("header not immediately followed by package clause\n%s", src)
 	}
 }