[hongzhi-gao]

Description

Change

Add the C++ Session::executeFastLastDataQueryForOnePrefixPath API for tree-model prefixes. It calls the existing Fast Last Thrift RPC, rejects wildcard prefixes, and returns a SessionDataSet. Add an integration test for multiple devices, sparse latest values, an empty result, and wildcard rejection.

Performance test on a storage server

• Machine: 16 CPU cores, 31 GiB RAM; 1 ConfigNode + 1 DataNode.
• Workload: 400 devices × 100 series = 40,000 series. Results matched ordinary SELECT LAST ** for all 40,000 series.
• Measurement: 20 warm-up queries per method, then three runs of 100 alternating samples per method. Each sample includes querying, reading all rows, and closing the result set.

Query	Samples	Mean	P50	P95	P99	Maximum	Over 100 ms
Fast Last	300	56.84 ms	55.74 ms	61.02 ms	62.51 ms	83.31 ms	0
Ordinary SQL Last	300	107.62 ms	104.45 ms	119.62 ms	136.89 ms	146.81 ms	300

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This PR has:

• been self-reviewed.
• added comments describing the new public API and its constraints.
• added an integration test.
• been tested against a test IoTDB cluster.

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Key changed/added classes (or packages if there are too many classes) in this PR

• Session, SessionConnection, and sessionIT.cpp in iotdb-client/client-cpp

[hongzhi-gao]

Hi @jt2594838 @JackieTien97 @Caideyipi , could you please review this PR when you have a chance? Thanks!