feat: mark generated and identity columns across writers and DBML

- bun: scanonly+generated for GENERATED columns; scanonly+identity for ALWAYS identity (PK gets identity only)
- gorm: <-:false+generated / identity, same primary key rule
- dbml: write GENERATED/IDENTITY column notes and read them back into the model
- pgsql: emit generation/identity clauses in migration create-table and add-column, no DEFAULT
- readmes updated

pkg/readers/dbml/README.md

@@ -157,6 +157,7 @@ grammar and the supported-directive matrix.
 
 ## Notes
 
+- Column notes `GENERATED ALWAYS AS (expr) STORED` and `GENERATED ALWAYS|BY DEFAULT AS IDENTITY` set `Generated`/`GenerationExpression` and `Identity`/`IdentityGeneration`; they are not kept as comments
 - DBML is designed for database documentation and diagramming
 - Schema name defaults to `public`
 - Relationship cardinality is preserved

pkg/readers/dbml/generated_columns.go

@@ -0,0 +1,38 @@
+package dbml
+
+import (
+	"regexp"
+	"strings"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+var (
+	generatedNoteRegex = regexp.MustCompile(`(?is)^GENERATED\s+ALWAYS\s+AS\s*\((.*)\)\s*STORED$`)
+	identityNoteRegex  = regexp.MustCompile(`(?i)^GENERATED\s+(ALWAYS|BY\s+DEFAULT)\s+AS\s+IDENTITY$`)
+)
+
+// applyColumnMarkerNote interprets a column note written by the DBML writer for
+// GENERATED ... STORED and GENERATED ... AS IDENTITY columns, setting the matching
+// model fields. It returns true when the note was a marker, in which case it is not
+// a user comment.
+func applyColumnMarkerNote(column *models.Column, rawNote string) bool {
+	note := strings.TrimSpace(rawNote)
+	if len(note) >= 2 && (note[0] == '\'' || note[0] == '"') && note[len(note)-1] == note[0] {
+		note = note[1 : len(note)-1]
+	}
+	note = strings.ReplaceAll(strings.ReplaceAll(note, `\'`, `'`), `\\`, `\`)
+	note = strings.TrimSpace(note)
+
+	if m := generatedNoteRegex.FindStringSubmatch(note); m != nil {
+		column.Generated = true
+		column.GenerationExpression = strings.TrimSpace(m[1])
+		return true
+	}
+	if m := identityNoteRegex.FindStringSubmatch(note); m != nil {
+		column.Identity = true
+		column.IdentityGeneration = strings.Join(strings.Fields(strings.ToUpper(m[1])), " ")
+		return true
+	}
+	return false
+}

pkg/readers/dbml/reader.go

@@ -804,7 +804,9 @@ func (r *Reader) parseColumn(line, tableName, schemaName string) (*models.Column
 			} else if strings.HasPrefix(attr, "note:") {
 				// Parse column note/comment
 				note := strings.TrimSpace(strings.TrimPrefix(attr, "note:"))
-				column.Comment = strings.Trim(note, "'\"")
+				if !applyColumnMarkerNote(column, note) {
+					column.Comment = strings.Trim(note, "'\"")
+				}
 			} else if strings.HasPrefix(attr, "ref:") {
 				// Parse inline reference
 				// DBML semantics depend on context: