feat: Add request timeout for rpc

[charlesdong1991]

Purpose

Linked issue: close #398

Brief change log

• Add request_timout_ms config
• Add a new request timeout error variant
• Propagate new config to python and c++ bindings

Tests

Tests all pass locally.

API and Format

Documentation

[Copilot]

Pull request overview

Adds a configurable per-RPC request timeout to prevent client calls from hanging indefinitely when the server stops responding (closes #398), and threads the new setting through Rust + Python/C++ bindings.

Changes:

• Introduce request_timeout_ms configuration with a 30s default.
• Apply request-level timeout in the RPC client and add RpcError::RequestTimeout.
• Expose the new config in Python and C++ bindings.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
crates/fluss/src/rpc/server_connection.rs	Adds request-timeout handling around response await; includes new unit tests.
crates/fluss/src/rpc/error.rs	Adds RequestTimeout RPC error variant.
crates/fluss/src/config.rs	Adds request_timeout_ms config with default and debug/default wiring.
crates/fluss/src/client/connection.rs	Plumbs request_timeout_ms into RpcClient construction.
bindings/python/src/config.rs	Parses and exposes request_timeout_ms in Python binding config.
bindings/python/fluss/__init__.pyi	Adds Config.request_timeout_ms typing to Python stubs.
bindings/cpp/src/lib.rs	Extends C++ FFI config to include request_timeout_ms.
bindings/cpp/src/ffi_converter.hpp	Converts C++ Configuration.request_timeout_ms into FFI config.
bindings/cpp/include/fluss.hpp	Exposes request_timeout_ms on the public C++ Configuration struct.

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[fresh-borzoni]

@charlesdong1991 Ty for the PR, left comments, PTAL

[charlesdong1991]

I addressed your comments, thanks again. @fresh-borzoni PTAL

[fresh-borzoni]

@charlesdong1991 Ty, left small comment and also rust docs are missing

[fresh-borzoni]

@charlesdong1991 TY, LGTM