frank-default-small: 491520 context pool (163840 per slot x 3)

--ctx-size is the total pool divided among --parallel slots, so with
PARALLEL=3 the 160k target must be a 491520 pool (163840/slot) to
actually deliver 160k context per slot. Env, serve default, bats updated.

scripts/frank-default-small.env

@@ -43,11 +43,12 @@ ALIAS=frank-default-small
 BIND_ADDR=0.0.0.0
 LISTEN_PORT=7770
 
-# Three parallel slots, each with 160000 ctx. With PARALLEL=3 ik_llama
-# limits speculative decoding to a single slot, so SPEC stays none (MTP is
-# also disabled). The 3 slots triple the KV cache, so enough expert weights
-# are CPU-pinned for the cache to fit on the 24 GB card.
-CTX_SIZE=160000
+# Three parallel slots sharing a 491520 total context pool (491520/3 =
+# 163840 per slot — the requested 160k). With PARALLEL=3 ik_llama limits
+# speculative decoding to a single slot, so SPEC stays none (MTP is also
+# disabled). The 3 slots + 480k pool make the KV cache large, so expert
+# weights are CPU-pinned for the cache to fit on the 24 GB card.
+CTX_SIZE=491520
 PARALLEL=3
 
 # Speculative decoding: DISABLED. ik_llama limits spec to a single slot; at