[igorbernstein2]

Set rows_limit = 1 on the built ReadRowsRequest proto instead of calling query.limit(1) in EnhancedBigtableStub.createPointReadCallable, preventing in-place mutation of the caller's Query instance when a point read or single-key readRows executes on the classic path.

[gemini-code-assist]

Code Review

This pull request modifies EnhancedBigtableStub to prevent mutating the original Query object when performing a point read. Instead of calling query.limit(1), the code now converts the query to a proto builder and sets the row limit on the proto representation directly. A corresponding unit test has been added to verify that reusing the query object does not carry over the single-row limit. There are no review comments to address, and the changes look solid.