feat(dbml): support multiline table notes in DBML

* Add parsing for triple-quoted table notes in DBML
* Update writer to format multiline notes correctly
* Enhance tests for multiline table notes handling

pkg/readers/dbml/reader.go

@@ -434,6 +434,9 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 	var currentSchema string
 	var inIndexes bool
 	var inTable bool
+	var inTableNote bool
+	var tableNoteLines []string
+	tableNoteStartLine := 0
 	var columnSeq uint
 	var lastIndex *models.Index // most recent index in the current Indexes block
 	lineNo := 0
@@ -443,7 +446,22 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 
 	for scanner.Scan() {
 		lineNo++
-		line := strings.TrimSpace(scanner.Text())
+		rawLine := scanner.Text()
+		line := strings.TrimSpace(rawLine)
+
+		// A table note can use DBML's triple-quoted form. Its contents must be
+		// consumed before normal parsing, otherwise each prose line is mistaken
+		// for a column declaration.
+		if inTableNote {
+			if line == "'''" {
+				currentTable.Description = strings.TrimSpace(strings.Join(tableNoteLines, "\n"))
+				inTableNote = false
+				tableNoteLines = nil
+				continue
+			}
+			tableNoteLines = append(tableNoteLines, strings.TrimSpace(rawLine))
+			continue
+		}
 
 		// Skip empty lines and comments
 		if line == "" || strings.HasPrefix(line, "//") {
@@ -542,6 +560,12 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 		// Parse table note
 		if inTable && currentTable != nil && strings.HasPrefix(line, "Note:") {
 			note := strings.TrimPrefix(line, "Note:")
+			if strings.TrimSpace(note) == "'''" {
+				inTableNote = true
+				tableNoteLines = nil
+				tableNoteStartLine = lineNo
+				continue
+			}
 			note = strings.Trim(note, " '\"")
 			currentTable.Description = note
 			continue
@@ -580,6 +604,13 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 		}
 	}
 
+	if err := scanner.Err(); err != nil {
+		return nil, fmt.Errorf("failed to scan DBML: %w", err)
+	}
+	if inTableNote {
+		return nil, fmt.Errorf("dbml: line %d: unterminated triple-quoted table note", tableNoteStartLine)
+	}
+
 	// Assign pending constraints to their respective tables
 	for _, constraint := range pendingConstraints {
 		// Find the table this constraint belongs to