revert(vllm-phi4): back to canonical/official Phi-4 chat template

Operator chose option (ii): keep the OFFICIAL Phi-4 format globally rather than
impose Ollama's leaner scaffold on every phi4 consumer. Removes the
--chat-template override + the conf/phi4-chat-template.jinja file (90e08f0).
vLLM now uses the tokenizer's built-in template (system <|end|> present);
verified 7-token render via tokenize/detokenize. brokkr re-baselines its R15
canonical on the official scaffold so baseline == production.

stacks/vllm/compose.yaml

@@ -210,7 +210,6 @@ services:
       - "${PHI4_PORT}:8000"
     volumes:
       - /tank/aimodels/huggingface:/hfcache
-      - /opt/docker/conf/vllm/phi4-chat-template.jinja:/config/phi4-chat-template.jinja:ro
     environment:
       - HF_HOME=/hfcache
       - HF_HUB_CACHE=/hfcache/hub
@@ -238,10 +237,6 @@ services:
       # FP8 KV cache — halves KV memory at 128K ctx on Ada (cc 8.9); near-lossless.
       - --kv-cache-dtype
       - ${PHI4_KV_CACHE_DTYPE}
-      # Ollama-matching scaffold (drops the system-turn <|end|>) so vLLM reproduces
-      # brokkr's R15 canonical baseline. See conf/phi4-chat-template.jinja.
-      - --chat-template
-      - /config/phi4-chat-template.jinja
     deploy:
       resources:
         reservations: