feat(vllm): add phi4-mini FP8 summarizer/dreamer on ana-ml2; retire granite from llama-swap

phi4-mini supersedes the granite-4-small llama-swap pin as the summarizer +
dreaming agent. New vllm-phi4 service: Phi-4-mini-instruct, vLLM-native FP8
(near-lossless on RTX 6000 Ada cc 8.9), 50K ctx, FP8 KV cache, GPU 1, :8004.

llama-swap: removed granite-4-small (depinned) + granite-4-micro config —
both superseded. CONFIG ONLY; the GGUFs stay on disk. Frees granite-4-small's
~24 GB (it was pinned at 120K ctx).

Placement: phi4 on GPU 1 with the embed/rerank/reward trio (~1.2 GB margin at
50K); keeps GPU 0 clear for llama-swap heavy models. docs/roadmap.md captures
the deferred vLLM observability (Langfuse req/resp tracing + Prometheus/Grafana).

Deploy order: llama-swap config (free granite) -> vllm-phi4 -> repoint nevermore.

stacks/llama-swap/conf/config.yaml

@@ -445,36 +445,18 @@ models:
   # GRANITE MODELS (IBM)
   # ==========================================================================
 
-  "granite-4-small":
-    name: "Granite 4.0 Small Q4_K_M"
-    description: "IBM Granite 4.0 Small. Deterministic utility model for structured tasks."
-    ttl: 0   # pinned — member of the `pinned` group, never unloads
-    cmd: |
-      /app/llama-server
-      --context-shift
-      --model /models/unsloth_granite-4.0-h-small-GGUF/granite-4.0-h-small-Q4_K_M.gguf
-      --port ${PORT}
-      --n-gpu-layers 999
-      --ctx-size 120000
-      --flash-attn on
-      --top-p 1.0
-      --temp 0.0
-      --top-k 0
+  # ── "granite-4-small" REMOVED 2026-06-04 ──────────────────────────────────
+  # Superseded by phi4-mini (summarizer + dreaming agent), now served via vLLM
+  # FP8 on ana-ml2 (stacks/vllm → vllm-phi4, :8004). It was pinned at 120K ctx
+  # (~24 GB resident: ~6 GB weights + ~18 GB KV); removing it reclaims that VRAM.
+  # DOWNSTREAM: repoint the news-digest curator from this llama-swap endpoint to
+  # the phi4-mini vLLM endpoint at/before deploy.
 
-  "granite-4-micro":
-    name: "Granite 4.0 Micro Q4_K_M"
-    description: "IBM Granite 4.0 Micro. Ultra-lightweight for fast structured responses."
-    ttl: 600
-    cmd: |
-      /app/llama-server
-      --context-shift
-      --model /models/ibm-granite_granite-4.0-micro-GGUF/granite-4.0-micro-Q4_K_M.gguf
-      --port ${PORT}
-      --n-gpu-layers 999
-      --ctx-size 32768
-      --flash-attn on
-      --temp 0.0
-      --top-p 1.0
+  # ── "granite-4-micro" config REMOVED 2026-06-04 ───────────────────────────
+  # Retired from llama-swap alongside granite-4-small (both superseded by
+  # phi4-mini). Per operator: CONFIG ONLY — the GGUF stays on disk at
+  # /models/ibm-granite_granite-4.0-micro-GGUF/granite-4.0-micro-Q4_K_M.gguf
+  # (NOT deleted), so this entry can be restored later if needed.
 
   # ==========================================================================
   # JUDGE / EVAL MODELS
@@ -605,13 +587,12 @@ groups:
   #
   # Current pins:
   #   qwen3.5-9b      — ~6 GB at Q4 + KV. General-purpose chat baseline.
-  #   granite-4-small — ~5-6 GB at Q4_K_M + 120K KV. Used by news-digest
-  #                     curator twice daily; pinning avoids the cold-load
-  #                     latency and prevents qwen3.6-27b (and similar)
-  #                     from evicting it when both are needed concurrently.
-  # VRAM budget: ~12 GB persistent in the pin slot. Single RTX 6000 Ada
-  # is 48 GB, so this leaves ~36 GB for whichever non-pinned model the
-  # user invokes alongside (qwen3.6-27b at ~30 GB fits cleanly).
+  # VRAM budget: ~6 GB persistent in the pin slot. Single RTX 6000 Ada
+  # is 48 GB, so this leaves ~40 GB for whichever non-pinned model the
+  # user invokes alongside.
+  #
+  # granite-4-small WAS pinned here; removed 2026-06-04 — superseded by
+  # phi4-mini (vLLM FP8, stacks/vllm → vllm-phi4). Freed ~24 GB (120K KV).
   #
   # qwen3.6-35-a3b WAS in this group; removed 2026-04-27 because its
   # ~29 GB at Q6_K_XL pushed concurrent loads OOM. Now lives outside
@@ -622,4 +603,3 @@ groups:
     persistent: true
     members:
       - "qwen3.5-9b"
-      - "granite-4-small"