Diagnostic baseline v2: also disable MoCo queue

The mutex-only run still collapsed at epoch 1 — same pattern as the DSS
run. Val loss locks to log(8) ≈ 2.08 (uniform over the in-batch sat),
train loss grows monotonically (4.80 → 5.56), train R@1 drops 7.79% →
0.34%. Mode collapse, not sampler-induced.

The smoking gun is the queue: WeightedInfoNCELoss (the OLD-run loss)
silently ignored `queue_negatives`, so the OLD-run effective task was
in-batch-only contrast against 8 negatives. Switching to InfoNCELoss
made the queue active — 4096 stale embeddings without a momentum encoder
to keep them consistent with the live model. With the trimmed adapter
surface (MONA in last 12/24 blocks → 3.5M trainable), the model can't
reconcile fresh representations against stale negatives and collapses.

Disable the queue entirely (`neg_bank_size = 0`). Matches OLD's effective
setup — same 8 in-batch negatives, but with the new SymmetricInfoNCE +
mutex sampler + tau clamp 0.1 + per-sample mask + full-gallery eval.

Output → `out/gtauav/baseline_inbatch` (separate from the failed mutex run).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

conf/gtauav_baseline.gin

@@ -13,9 +13,16 @@
 include 'conf/gtauav_balanced.gin'
 
 TrainConfigGTAUAV.baseline_mode = True
-TrainConfigGTAUAV.output_dir = "out/gtauav/baseline_mutex"
+TrainConfigGTAUAV.output_dir = "out/gtauav/baseline_inbatch"
 TrainConfigGTAUAV.use_gradcam = False
 
 # ---- Diagnostic overrides ----
-TrainConfigGTAUAV.sampler_type = "mutex"  # was "dss" — disable hard-batch construction
-InfoNCELoss.hard_mining_k = 0  # was 512 — use full queue without per-query top-K
+# Previous mutex-only run still collapsed at epoch 1 (val loss locked at log(8)).
+# Hypothesis refined: the MoCo-style queue stays stale because we have no
+# momentum encoder, and with reduced trainable surface (MONA-12) the model
+# can't reconcile fresh representations against 4096 stale negatives —
+# mode collapse. Disable the queue entirely so InfoNCE sees only the 8
+# fresh in-batch negatives, matching the OLD run's effective setup.
+TrainConfigGTAUAV.sampler_type = "mutex"  # was "dss"
+TrainConfigGTAUAV.neg_bank_size = 0  # was 4096 — disable MoCo queue (no momentum encoder)
+InfoNCELoss.hard_mining_k = 0  # was 512 — irrelevant when queue is empty