fix(argo): mount feature-cache PVC + correct smoke paths

- Template was missing feature-cache PVC mount on run-cell; trained
  checkpoints + predecoded data live at /feature-cache/* on the
  feature-cache-pvc claim. Mount it the same way alpha-perception does.
- sweep_smoke.yaml referenced /data/* (no such mount) and a 40-char
  SHA path for the checkpoint dir. alpha-perception-runs subdirs are
  9-char short SHAs; data path is /mnt/training-data/* (matches mount).

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

config/ml/sweep_smoke.yaml

@@ -7,7 +7,7 @@
 # Bounded by max_events for fast feedback.
 
 base:
-  data: /data/futures-baseline-mbp10/ES.FUT
+  data: /mnt/training-data/futures-baseline-mbp10/ES.FUT
   predecoded_dir: /feature-cache/predecoded
   n_parallel: 1
   decision_stride: 1
@@ -17,7 +17,8 @@ base:
   max_lots: 5
   max_events: 100000
   seed: 12648430
-  checkpoint: /feature-cache/alpha-perception-runs/58b5ebbd3819ce7fcb70442f08413a5704bd97c3/trunk_best_h6000.bin
+  # alpha-perception-runs dirs use the 9-char short SHA, not the full 40-char SHA.
+  checkpoint: /feature-cache/alpha-perception-runs/58b5ebbd3/trunk_best_h6000.bin
 
 cells:
   - name: smoke

infra/k8s/argo/lob-backtest-sweep-template.yaml

@@ -99,6 +99,9 @@ spec:
     - name: cargo-target-cuda
       persistentVolumeClaim:
         claimName: cargo-target-cuda
+    - name: feature-cache
+      persistentVolumeClaim:
+        claimName: feature-cache-pvc
 
   templates:
     # ── DAG entrypoint ──────────────────────────────────────────────
@@ -269,6 +272,8 @@ spec:
         volumeMounts:
           - name: training-data
             mountPath: /mnt/training-data
+          - name: feature-cache
+            mountPath: /feature-cache
         args:
           - |
             set -e