test: Add Table B+ Tree row operation tests

[ApostolisFalaras]

Description

Add tests for Table row operations that coordinate the primary and secondary B+ Tree indexes.

Physical table creation, materialization, truncation, drop, and Pager persistence are already covered separately.

Tasks

• Test row insertion through the primary index
• Test secondary-index entries created during insertion
• Test duplicate PRIMARY KEY rejection
• Test UNIQUE constraint rejection
• Test primary-key row lookup
• Test secondary-index row lookup
• Test full table scan
• Test index range scan
• Test tombstoned rows are skipped
• Test row update without changing indexed columns
• Test row update that changes a secondary-index key
• Test row update that changes the primary key
• Test row deletion
• Test secondary-index entries are removed after deletion
• Test row count after successful insertions and deletions
• Test failure consistency when one index operation fails

Acceptance Criteria

• Inserted rows are reachable through the appropriate indexes.
• Primary and secondary indexes remain synchronized.
• Duplicate and UNIQUE violations are rejected.
• Table scans return all live rows.
• Range scans return the expected rows in index order.
• Updates correctly replace affected index entries.
• Deleted or tombstoned rows are not returned.
• Row count remains consistent.
• Failed operations do not leave partially updated index state.

Depends On

• feat: Implement Table row insertion
• feat: Implement Table row lookup and scan operations
• feat: Implement Table row update
• feat: Implement Table row deletion
• feat: Implement Index exact lookup and range scan operations
• feat: Implement Index entry insertion
• feat: Implement Index entry deletion