docs: frank-medium is llama.cpp with DFlash2 on both cards

The runbook for the new deployment, plus the sweep of everything that still
described the vllm-radiance replica pair: the vault index and its ACTIVE
marker, the superseded banner on the radiance page, the pointer from the
ROCmFPX page, the homepage card, the Grafana dashboard description and the
observability page's scrape table.

The new page carries the two facts a future agent needs and the flags do not
say: llama.cpp's layer split is what lets BOTH cards serve ONE model without
any collective (vLLM's PP handoff is an RCCL send/recv, which is the primitive
this host cannot dispatch), and the rocBLAS Tensile-path trap that makes a
healthy-looking build fail on the first request.

shared/grafana/provisioning/dashboards/llm-fleet.json

@@ -1,7 +1,7 @@
 {
   "uid": "llm-fleet",
   "title": "LLM fleet — capacity and reuse",
-  "description": "The signals that explain frank-medium under load, from the 2026-09-16 capacity work: per-card KV fill, queue depth, prefix-cache reuse, and request latency. frank-small (llama.cpp on Dankclaw's RTX 3090) exports throughput counters and appears in the same endpoint picker; frank-large runs the halogen engine, which publishes /health, /cache and /v1/* and no metrics endpoint at all, so it cannot appear here. See serverAppConfigs-docs/LLM/frank-medium-radiance-mxfp4.md for the numbers these panels are read against.",
+  "description": "The signals that explain frank-medium under load, from the 2026-09-16 capacity work. The panels read the endpoint's own counters: KV fill, queue depth, prefix-cache reuse, and request latency. frank-small (llama.cpp on Dankclaw's RTX 3090) exports throughput counters and appears in the same endpoint picker; frank-large runs the halogen engine, which publishes /health, /cache and /v1/* and no metrics endpoint at all, so it cannot appear here. See serverAppConfigs-docs/LLM/frank-medium-llamacpp-dflash2.md for the numbers these panels are read against.",
   "tags": [
     "llm",
     "frank-medium",