[PR] feat(python): support streaming SQL results [paimon-rust]

["plusplusjiajia (via GitHub)" <gi...@apache.org>]

plusplusjiajia opened a new pull request, #1103:
URL: https://github.com/apache/paimon-rust/pull/1103

   ### Purpose
   
   Linked issue: N/A.
   
   Python `SQLContext.sql()` and `sql_with_options()` collect all result batches before returning. Add `sql_stream()` and `sql_stream_with_options()` so callers can consume PyArrow batches incrementally and stop reading early.
   
   ### Brief change log
   
   - Return the existing `RecordBatchReader` from DataFusion's execution stream, preserving SQL error conversion and PyArrow string compatibility.
   - Reuse the reader's cancellation support and release its stream on EOF or a read error.
   - Add regression coverage for multiple batches, Paimon reads, empty results, errors after a successful batch, early close, and `SQLOptions` restrictions.
   
   ### Tests
   
   - Python: 205 tests passed across `test_sql_stream.py`, `test_datafusion.py`, and `test_read.py`, using CPython 3.10 and locally generated filesystem Paimon fixtures.
   - `cargo test --locked -p pypaimon_rust --lib`: 92 tests passed, including pending-read cancellation and stream cleanup, using an embedded CPython 3.11 interpreter.
   - `cargo clippy --locked -p pypaimon_rust --all-targets --no-deps -- -D warnings`: passed.
   - `cargo fmt --all -- --check` and `git diff --check`: passed.
   
   ### API and Format
   
   Adds `SQLContext.sql_stream(sql)` and `SQLContext.sql_stream_with_options(sql, options)`, both returning `RecordBatchReader`.
   
   Existing readers shared by `TableRead.read_arrow()` and shard updates now release their stream on EOF or an underlying read error. The failing read raises the error; subsequent reads return `None`. Callers must create a new reader to retry.
   
   The binding avoids collecting the entire output, while operators such as sorting and aggregation may still buffer data. No storage format changes.
   
   ### Documentation
   
   Adds Python type stubs and a README example using `contextlib.closing` to release the reader when iteration stops early.
   


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Re: [PR] feat(python): support streaming SQL results [paimon-rust]

["JingsongLi (via GitHub)" <gi...@apache.org>]

JingsongLi merged PR #1103:
URL: https://github.com/apache/paimon-rust/pull/1103


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