Per spec §3.1, §2.3. Controller A computes tau-change EMA with
first-observation bootstrap + Wiener-α floor 0.4 (co-adapting closed
loop); trigger when EMA < max(noise_floor/4, noise_floor/16); ISV-derived
hard cap from observed MAD/median dispersion in first 100 steps.
execute_transition() dispatches the 5 device kernels in order:
tau_sort → bucket_assign → bucket_iqr → tau_reorder → heads_compact.
All-on-device per feedback_no_htod_htoh_only_mapped_pinned (one-time
static-constant upload at transition is allowed off-hot-path).
Returns raw Q1/Q3 in BucketRoutingMetadata.bucket_tau_iqr_{lo,hi}_d;
slack_factor=sqrt(Q3/Q1) widening kernel applied by trainer in Task 9.
3 CPU-only unit tests verify Controller A's first-obs bootstrap,
threshold-trigger, and ISV-cap-trigger semantics.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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