Fix/postgres alias column autocomplete

[m-tonon]

This PR implements a shared SQL autocomplete registration flow for both the editor and notebook views, improving lifecycle management and preventing stale or duplicate Monaco providers.

Changes:

• Added useSqlAutocompleteRegistration hook to manage SQL autocomplete for active connections
• Updated NotebookView to utilize the new hook, passing the effective schema and active state
• Refactored Editor to replace direct SQL autocomplete registration with the hook
• Introduced disposeSqlAutocomplete to clean up resources on connection changes, reconnect, and failures
• Added support for schema-qualified table names, double-quoted identifiers, and alias resolution in PostgreSQL
• Added regression tests for schema-qualified tables, quoted identifiers, and autocomplete disposal

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Closes #266