fix: reduce modkit SLURM memory from 192GB to 48GB

Actual peak memory for modkit_extract_calls and modkit_extract_full is
~27GB based on sacct data. 192GB was an overcorrection after earlier OOM
at 24GB. 48GB provides ~1.8x headroom over observed peak.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jayhesselberth

cluster/slurm/config.yaml

@@ -66,13 +66,13 @@ set-resources:
   # Modkit modification extraction - high memory
   modkit_extract_calls:
     runtime: 360               # 6 hours
-    mem_mb: 192000             # 192GB
+    mem_mb: 48000              # 48GB (peak ~27GB observed)
     cpus_per_task: 4
 
   # Modkit full modification extraction
   modkit_extract_full:
     runtime: 360               # 6 hours
-    mem_mb: 192000             # 192GB
+    mem_mb: 48000              # 48GB (peak ~27GB observed)
     cpus_per_task: 4
 
   # WarpDemuX demultiplexing rules