QUOTE_IDENT() is now used in update_date_columns_default() and
update_updated_at_column_for_tables() to handle mixed-case table names.
Added BASE TABLE filter to update_date_columns_default() to exclude
FDW foreign tables (matching what update_updated_at_column_for_tables
already did). Fixed || to OR for logical disjunction in column_default
check. Added quoteIdentifier() helper in PHP for dynamic SQL.