fix(blob): validate entry integrity on reads

[QuakeWang]

Purpose

BLOB entries contain a magic number, embedded length, and CRC32, but inline reads previously fetched only payload bytes. Corrupted entries could therefore be returned as valid data.

Brief change log

• Validate entry magic, length, and CRC32 for scalar and inline ARRAY<BLOB> reads.
• Reject short or corrupted entries, including empty BLOB values.
• Preserve descriptor-mode range-only behavior and add corruption regression tests.

Tests

• cargo fmt --all -- --check
• cargo clippy --locked --all-targets --workspace --features fulltext,vortex -- -D warnings
• cargo test --locked -p paimon --all-targets --features fulltext,vortex

API and Format

Documentation

[JingsongLi]

+1