feat(blob): add create-time schema contract checks

[QuakeWang]

Purpose

Linked issue: part of #228

This PR hardens the create-time schema contract for BLOB columns.

After BlobType groundwork landed, Rust still relied on scattered runtime rejections for some invalid table shapes. This change moves the basic table-creation checks to schema construction so invalid BLOB table definitions fail earlier and more consistently.

This PR is intentionally limited to create-time validation. It does not add .blob file-format dispatch or read path support.

Brief change log

• add create-time BLOB validation in Schema::new()
• require data-evolution.enabled = true when top-level BLOB columns exist
• reject tables whose top-level columns are all BLOB
• reject top-level BLOB columns in partition keys
• add schema-level tests for the accepted and rejected cases
• update the existing table_write test fixture to satisfy the new schema contract

Tests

API and Format

Documentation

[JingsongLi]

+1