fix(core): enforce bulkWrite batch response type, cardinality, and correlation

[yinlianghui]

Baseline and relation to #2678/#2680

• Verified at 98874656ffc50ce1531af52346228ffcdda73fba.
• Introduced with perf(seed,import): route bulk writes through the engine's batch insert path #2680's shared bulkWrite helper (21420d9f82e); the helper is unchanged after merge.
• perf(seed,import): route bulk writes through the engine's batch insert path #2680 promises preserved per-row result ordering while moving writes to batches.

Minimal reproduction

Call bulkWrite for multiple input rows with writeBatch returning each of:

1. fewer records than inputs;
2. extra records;
3. records in reverse order;
4. a non-array object.

All unsafe variants reproduced 2/2.

Expected / actual

• Expected: the batch boundary rejects or safely degrades responses that cannot prove one output per input in contract order.
• Actual: records[i] is trusted without array/type/cardinality validation. Missing records become clean {ok:true, record:undefined}, extras are ignored, and reversed IDs are assigned to the wrong input rows.

Impact

The real import path confirmed downstream corruption: a short response reported a create with no ID; a reversed response mis-correlated IDs; async undo then left a created record permanently untracked.

Evidence and exclusions

• Source: packages/core/src/utils/bulk-write.ts around the writeBatch success loop.
• Import consumers: packages/rest/src/import-runner.ts result/undo mapping.
• An undefined response throws and degrades safely; that subcase is not the bug.
• Generic correlation may require an explicit validator/key contract; at minimum array type and exact cardinality must be enforced before success.

Required regression tests

• Reject/degrade non-array, short, and long responses.
• Define and test correlation/order validation for returned records.
• Integration test that import result IDs and undo logs remain aligned with original rows.

[yinlianghui]

暂时关闭，等待人工逐项复核。当前 QA 复现证据保留；本次关闭不表示问题已修复、无效或重复。人工确认后将按需重新打开。