Add non-record streaming legal TTT late-block submission

[simon-marcus]

Summary

This adds a non-record track_10min_16mb submission documenting a full 8xH100 run built from the March 23 leader with a different legal TTT protocol.

Why submit this

This is intentionally framed as a non-record submission. The main value is to provide the community with a clean comparison between:

• the March 23 leader's chunked score-first legal TTT over all blocks
• a streaming legal TTT variant that adapts online and only updates the last 4 blocks

What changed relative to the March 23 leader

• kept the same base model stack and LeakyReLU(0.5)^2 activation
• switched eval-time adaptation to TTT_MODE=stream
• used TTT_PARAM_MODE=late_blocks with TTT_LAST_N_BLOCKS=4
• included explicit preflight and run logs for reproducibility

Result

Final legal_ttt_exact on the included run:

• 1.12082320

This slightly trails the March 23 leader's seed-1337 1.11922988, but the intermediate pre-TTT and sliding-window metrics are very close, which makes this a useful data point on the TTT protocol itself.

Included artifacts

• train_gpt.py
• train_seed1337.log
• runpod_launch.log
• preflight.log
• submission.json