feat: Implemented schema based fetching

[Yashh56]

This pull request introduces schema (database) selection support across the database explorer, improving multi-schema database handling and user experience. It adds lightweight schema name fetching for all supported databases, updates the backend and frontend to support schema selection, and ensures that table operations and migrations work correctly with the selected schema. Additionally, it adds a refresh button to the migrations panel and updates a dependency.

Backend support for schema selection:

• Added listSchemaNames functions to the MariaDB, MySQL, and Postgres connector files to efficiently fetch schema (database) names for use in schema selectors. [1] [2] [3]
• Implemented listSchemaNames method in QueryExecutor to route schema name requests to the appropriate connector.
• Added a new RPC handler and endpoint (db.listSchemas) to expose schema names to the frontend. [1] [2]

Frontend schema selection and usage:

• Updated hooks and components to support schema selection, including fetching schema names, tracking the selected schema, and passing it to table queries and creation dialogs. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]

Migration generator improvements:

• Standardized table reference formatting in migration SQL generation to always include the schema/database prefix for all database types, improving consistency and correctness. [1] [2] [3]

UI/UX enhancements:

• Added a refresh button to the migrations panel, allowing users to manually refresh migration and schema information. [1] [2] [3]

Dependency updates:

• Upgraded the baseline-browser-mapping package to version 2.9.19 in package.json and pnpm-lock.yaml. [1] [2] [3] [4]