Refactor Firebird result row building and BLOB reads

[terrymanu]

No description provided.

[terrymanu]

Result

Review Result: Mergeable

The latest public head of PR #39484, 2eb665ca77b96c768685e0babe8a55580efcad02, has passed the code-correctness review. No blocking issue met the Finding Proof Gate.

Evidence

• Execute and Fetch now share FirebirdBinaryRowBuilder, preserving cell order, JDBC type mapping, and original data references: builder.
• FirebirdBlobReadCache.readSegment keeps the original array with an offset, copies only the returned segment, and removes the cursor when complete: cache.
• Get BLOB segment preserves EOF, PARTIAL, and COMPLETE states as well as the existing length limits: executor.
• BLOB info uses the cursor’s remaining length and retains the write-cache fallback: info executor.
• Tests cover row construction, empty and missing BLOBs, zero-length requests, partial and complete reads, consecutive reads, cursor isolation, and length fallback: changed test files.

Coverage

• Review range: base 228e98b3274695c14a2c07f76459c76943403099 through head 2eb665ca77b96c768685e0babe8a55580efcad02.
• The authoritative GitHub file list contains 10 files and matches the local triple-dot file list.
• The row-building, BLOB-cursor, and protocol-consumer behavior clusters completed root-cause, blast-radius, tests/runtime, and convergence review.
• Local verification: 43/43 focused tests passed; 263/263 Firebird module tests passed; affected production classes reached 100% class, line, and branch coverage.
• This is a Code Correctness Review and therefore assesses code-scope readiness only; GitHub Actions and CI status were not reviewed.