Support partitioned table in TableScan and TableRead

[luoyuxia]

Parent Issue

Part of #124 (support partitioned table)
Depends on #126 (BinaryRow deserialization), #127 (partition path generation)

Background

Currently, TableScan and TableRead do not support partitioned tables:

1. TableScan::plan_snapshot() discards partition info and builds wrong bucket paths ({base_path}/bucket-{bucket} instead of {base_path}/{partition_path}/bucket-{bucket})
2. TableRead::to_arrow() explicitly rejects partitioned tables with Unsupported error
3. No integration tests for partitioned table reading

What needs to be done

1. Fix TableScan to generate correct partition paths

• Pass partition type info (from TableSchema) into plan_snapshot(), or change it to an instance method that can access self.table.schema
• Decode partition bytes from ManifestEntry into BinaryRow using BinaryRow::from_bytes(arity, data)
• Use partition path utils (from Implement partition path generation (PartitionPathUtils) #127) to compute the partition path segment
• Construct bucket_path as {table_path}/{partition_path}/bucket-{bucket}
• Store actual decoded BinaryRow in DataSplit instead of empty BinaryRow::new(0)

2. Remove partitioned table read restriction in TableRead

• Remove the partition key check in TableRead::to_arrow() (read_builder.rs:88-95)
• ArrowReader should work without changes once paths are correct

3. Add integration tests

• Prepare test fixtures for partitioned tables (single and multiple partition keys)
• Integration test: read a partitioned table end-to-end, verify DataSplits have correct bucket_path with partition segments
• Verify partition column values are correct in returned RecordBatches

Affected files

• crates/paimon/src/table/table_scan.rs — plan_snapshot() method
• crates/paimon/src/table/read_builder.rs — TableRead::to_arrow() method
• crates/integration_tests/tests/ — new test file(s)

[QuakeWang]

I will do this task when #139 has been merged.