MiniKafka behavior matrix

This matrix binds each promised semantic to executable evidence.

Semantic	Evidence
Binary-safe batches and CRC	tests/unit/test_batch_codec.py
Sparse offset lookup	tests/unit/test_offset_index.py
Tail repair and closed-segment corruption	tests/log/test_recovery.py
Offset replay across segments	tests/log/test_partition_log.py
Keyed/sticky partitioning and batching	tests/producer/test_ordering.py, tests/producer/test_batching.py
Position, commit, rewind and restart	tests/consumer/test_positions.py, tests/reliability/test_offset_restart.py
Single group owner and generation fencing	tests/consumer/test_group_rebalance.py, tests/consumer/test_generation_fencing.py
Segment retention	tests/log/test_retention.py
Key compaction and failure-aware directory replacement	tests/log/test_compaction.py, tests/reliability/test_compaction_swap.py
Follower fetch, ISR and high watermark	tests/replication/test_follower_fetch.py, tests/replication/test_high_watermark.py
Ack modes and acknowledged-write loss	tests/replication/test_ack_modes.py, tests/reliability/test_lost_acked_write.py
Promotion fencing and divergent-tail truncation	test_old_leader_truncates_uncommitted_tail, tests/replication/test_promotion.py
Idempotent retry and restart rebuild	test_exact_retry_returns_original_offsets, tests/reliability/test_producer_state_restart.py
Transaction isolation and abort	tests/transaction/test_visibility.py, tests/transaction/test_abort.py
Atomic output and input offsets	test_output_and_input_offset_publish_together
Journal recovery	tests/reliability/test_transaction_restart.py
Direct/TCP parity	tests/adapters/test_direct_tcp_parity.py
Graceful close, crash, terminal failure	tests/reliability/test_shutdown.py, tests/reliability/test_background_failure.py
Cross-feature closure and restart	tests/test_final_acceptance.py

The JSON/TCP adapter proves boundary translation only. The direct API remains the authoritative route for core and failure-semantics tests.