[TASK-248] Builder pattern for CPP

[fresh-borzoni]

Summary

closes #248

C++ Builder Pattern for Log Scanners

Replaced four separate scanner methods on Table with a fluent TableScan builder.

Before

table.NewLogScanner(scanner);
table.NewLogScannerWithProjection(columns, scanner);
table.NewRecordBatchLogScanner(scanner);
table.NewRecordBatchLogScannerWithProjection(columns, scanner);

After

  table.NewScan().CreateLogScanner(scanner);
  table.NewScan().Project(columns).CreateLogScanner(scanner);
  table.NewScan().CreateRecordBatchScanner(scanner);
  table.NewScan().Project(columns).CreateRecordBatchScanner(scanner);

[fresh-borzoni]

@luoyuxia @zhaohaidao Appreciate you review here. PTAL 🙏

[Copilot]

Pull request overview

This PR refactors the C++ bindings to use a builder pattern for creating log scanners, aligning with the Rust and Java APIs. The refactoring replaces four separate methods (NewLogScanner, NewLogScannerWithProjection, NewRecordBatchLogScanner, NewRecordBatchLogScannerWithProjection) on the Table class with a fluent TableScan builder pattern.

Changes:

• Introduced TableScan builder class with Project() method for column projection
• Replaced four scanner creation methods with NewScan() returning a TableScan builder
• TableScan provides CreateLogScanner() and CreateRecordBatchScanner() terminal methods
• Updated all example code to use the new fluent API

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
bindings/cpp/include/fluss.hpp	Added TableScan builder class; removed four scanner methods from Table class; added NewScan() method
bindings/cpp/src/table.cpp	Implemented TableScan builder with projection support; consolidated scanner creation logic into two terminal methods
bindings/cpp/examples/example.cpp	Updated all scanner creation calls to use the new builder pattern API

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[luoyuxia]

@fresh-borzoni Thanks for the pr. Only one minor comment. PTAL

[fresh-borzoni]

@luoyuxia Ty for the review. Addressed, PTAL 🙏

[luoyuxia]

@fresh-borzoni Thanks. LGTM.. Merge it. @zhaohaidao Please note the api changes for creating log scanner and feel free to left comment.