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/drizzle/template_data.go

@@ -4,16 +4,14 @@ import (
 	"sort"
 	"strings"
 
-	"git.warky.dev/wdevs/relspecgo/pkg/buildinfo"
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
 )
 
 // TemplateData represents the data passed to the template for code generation
 type TemplateData struct {
-	GeneratedBy string
-	Imports     []string
-	Enums       []*EnumData
-	Tables      []*TableData
+	Imports []string
+	Enums   []*EnumData
+	Tables  []*TableData
 }
 
 // EnumData represents an enum in the schema
@@ -61,10 +59,9 @@ type IndexData struct {
 // NewTemplateData creates a new TemplateData
 func NewTemplateData() *TemplateData {
 	return &TemplateData{
-		GeneratedBy: buildinfo.GeneratedComment(),
-		Imports:     make([]string, 0),
-		Enums:       make([]*EnumData, 0),
-		Tables:      make([]*TableData, 0),
+		Imports: make([]string, 0),
+		Enums:   make([]*EnumData, 0),
+		Tables:  make([]*TableData, 0),
 	}
 }