feat(ui): add relationship management features in schema editor

- Implement functionality to create, update, delete, and view relationships between tables.
- Introduce new UI screens for managing relationships, including forms for adding and editing relationships.
- Enhance table editor with navigation to relationship management.
- Ensure relationships are displayed in a structured table format for better usability.

pkg/readers/doc.go

@@ -0,0 +1,53 @@
+// Package readers provides interfaces and implementations for reading database schemas
+// from various input formats and data sources.
+//
+// # Overview
+//
+// The readers package defines a common Reader interface that all format-specific readers
+// implement. This allows RelSpec to read database schemas from multiple sources including:
+//   - Live databases (PostgreSQL, SQLite)
+//   - Schema definition files (DBML, DCTX, DrawDB, GraphQL)
+//   - ORM model files (GORM, Bun, Drizzle, Prisma, TypeORM)
+//   - Data interchange formats (JSON, YAML)
+//
+// # Architecture
+//
+// Each reader implementation is located in its own subpackage (e.g., pkg/readers/dbml,
+// pkg/readers/pgsql) and implements the Reader interface, supporting three levels of
+// granularity:
+//   - ReadDatabase() - Read complete database with all schemas
+//   - ReadSchema() - Read single schema with all tables
+//   - ReadTable() - Read single table with all columns and metadata
+//
+// # Usage
+//
+// Readers are instantiated with ReaderOptions containing source-specific configuration:
+//
+//	// Read from file
+//	reader := dbml.NewReader(&readers.ReaderOptions{
+//	    FilePath: "schema.dbml",
+//	})
+//	db, err := reader.ReadDatabase()
+//
+//	// Read from database
+//	reader := pgsql.NewReader(&readers.ReaderOptions{
+//	    ConnectionString: "postgres://user:pass@localhost/mydb",
+//	})
+//	db, err := reader.ReadDatabase()
+//
+// # Supported Formats
+//
+//   - dbml: Database Markup Language files
+//   - dctx: DCTX schema files
+//   - drawdb: DrawDB JSON format
+//   - graphql: GraphQL schema definition language
+//   - json: JSON database schema
+//   - yaml: YAML database schema
+//   - gorm: Go GORM model structs
+//   - bun: Go Bun model structs
+//   - drizzle: TypeScript Drizzle ORM schemas
+//   - prisma: Prisma schema language
+//   - typeorm: TypeScript TypeORM entities
+//   - pgsql: PostgreSQL live database introspection
+//   - sqlite: SQLite database files
+package readers

pkg/readers/sqlite/queries.go

@@ -106,7 +106,7 @@ func (r *Reader) queryColumns(tableName string) (map[string]*models.Column, erro
 		}
 
 		// Check for autoincrement (SQLite uses INTEGER PRIMARY KEY AUTOINCREMENT)
-		if pk > 0 && strings.ToUpper(dataType) == "INTEGER" {
+		if pk > 0 && strings.EqualFold(dataType, "INTEGER") {
 			column.AutoIncrement = r.isAutoIncrement(tableName, name)
 		}
 

pkg/readers/sqlite/reader.go

@@ -187,35 +187,35 @@ func (r *Reader) close() {
 func (r *Reader) mapDataType(sqliteType string) string {
 	// SQLite has a flexible type system, but we map common types
 	typeMap := map[string]string{
-		"INTEGER":  "int",
-		"INT":      "int",
-		"TINYINT":  "int8",
-		"SMALLINT": "int16",
-		"MEDIUMINT": "int",
-		"BIGINT":   "int64",
-		"UNSIGNED BIG INT": "uint64",
-		"INT2":     "int16",
-		"INT8":     "int64",
-		"REAL":     "float64",
-		"DOUBLE":   "float64",
-		"DOUBLE PRECISION": "float64",
-		"FLOAT":    "float32",
-		"NUMERIC":  "decimal",
-		"DECIMAL":  "decimal",
-		"BOOLEAN":  "bool",
-		"BOOL":     "bool",
-		"DATE":     "date",
-		"DATETIME": "timestamp",
-		"TIMESTAMP": "timestamp",
-		"TEXT":     "string",
-		"VARCHAR":  "string",
-		"CHAR":     "string",
-		"CHARACTER": "string",
+		"INTEGER":           "int",
+		"INT":               "int",
+		"TINYINT":           "int8",
+		"SMALLINT":          "int16",
+		"MEDIUMINT":         "int",
+		"BIGINT":            "int64",
+		"UNSIGNED BIG INT":  "uint64",
+		"INT2":              "int16",
+		"INT8":              "int64",
+		"REAL":              "float64",
+		"DOUBLE":            "float64",
+		"DOUBLE PRECISION":  "float64",
+		"FLOAT":             "float32",
+		"NUMERIC":           "decimal",
+		"DECIMAL":           "decimal",
+		"BOOLEAN":           "bool",
+		"BOOL":              "bool",
+		"DATE":              "date",
+		"DATETIME":          "timestamp",
+		"TIMESTAMP":         "timestamp",
+		"TEXT":              "string",
+		"VARCHAR":           "string",
+		"CHAR":              "string",
+		"CHARACTER":         "string",
 		"VARYING CHARACTER": "string",
-		"NCHAR":    "string",
-		"NVARCHAR": "string",
-		"CLOB":     "text",
-		"BLOB":     "bytea",
+		"NCHAR":             "string",
+		"NVARCHAR":          "string",
+		"CLOB":              "text",
+		"BLOB":              "bytea",
 	}
 
 	// Try exact match first