Manuscript revision and pending experiment work, snapshot before restructuring

Clarity pass over the main text (36-item audit), Discussion rewrite and cut,
acknowledgements, Souly et al. as ref 62, lettered SI panels, model section
moved under Results; plus the untracked curriculum/society/compose/smol
configs, runners, figures, stats and tests that the SI already cites.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y64o8FKP7rCuXzC48pxpMm

configs/llm/compose_gate_math500.yaml

@@ -0,0 +1,34 @@
+# Generation-0 gate, second configuration (prereg v3 §4a): the composed target is MATH-500
+# (competition maths, level >= 3, numeric answers), and merge weights are *selected* on a disjoint
+# validation split rather than fixed at 0.5/0.5.
+#
+# Why: on GSM8k-Hard the code parent alone reaches 0.427, because once code removes the arithmetic
+# burden the base's own reasoning suffices — so maths is not scarce and E8's premise fails. MetaMathQA
+# is built from GSM8K *and* MATH, so MATH-500 tests reasoning the specialist has and the base lacks.
+# Founders are shared with the first gate (same experiment name), so this costs evaluation only.
+experiment: llm_compose_gate
+kind: llm_compose
+base_model: Qwen/Qwen2.5-1.5B
+seed: 1
+generations: 0
+arms: [dry]
+target: math500
+n_hard: 120               # test split (level>=3 pool is 271; 70% test / 30% val, disjoint)
+n_hard_val: 50            # val split, screens the merge weights only
+merge_weights: [[0.5, 0.5], [0.3, 0.7], [0.2, 0.8]]
+n_gsm8k: 100
+n_mbpp: 80
+n_probe: 40
+k_inherit: 300
+epochs: 3
+conf_gate: 0.85
+g: 0.10
+spec_train: 1200
+spec_epochs: 3
+max_new_tokens: 320
+batch_size: 16
+score_batch_size: 8
+train_batch_size: 2
+train_max_len: 448
+lora: {r: 16, alpha: 32}
+output: {dir: results/llm_compose_gate_math500}