Research llama.cpp runtimes + SGLang; fix AGENTS.md OKF spec link

Fan out subagents to compare mainline llama.cpp, charlie12345/ROCmFPX,
and ik_llama.cpp, then add their findings to the project knowledge base:
- docs/Research/Llama Cpp Runtimes.md  (positioning + quantization + server fit)
- docs/Research/Llama Cpp Code Diff.md (code-level quant diff, table, recommendations)
- docs/Research/SGLang.md              (what SGLang is, comparison, our-boxes fit)
- docs/Research/index.md               (Research progressive-disclosure index)
Cross-linked from docs/index.md (root) and docs/LLM/index.md.

AGENTS.md:
- Add Documentation Authoring section: docs/ is an OKF bundle; point doc authors
  at the canonical spec in the system-config knowledge base
  (~/.pi/agent/docs/references/okf-spec.md), not the orphaned
  docs/references/okf-spec.md; consolidate read-index/one-concept-per-file/
  progressive-disclosure/citation rules.
- Map AGENTS.md to docs_completeness.bats in the focused pre-commit hook (it was
  last committed before the hook existed and had no mapping).

docs/index.md

@@ -88,6 +88,9 @@ covers both workloads).
 - [[Service Research Brief]] — consolidated subagent research behind these pages
 - [[ComfyUI ROCm and Vulkan]] — live-verified GPU path for ComfyUI on Strix Halo
 - [[Lemonade and sd.cpp]] — the ggml-family image-generation alternative
+- [[Llama Cpp Runtimes]] — mainline vs charlie12345/ROCmFPX vs ik_llama.cpp: quantization + server fit
+- [[Llama Cpp Code Diff]] — code-level quantization diff of the three llama.cpp runtimes
+- [[SGLang]] — the structured-generation serving engine (llama.cpp/vLLM comparison + our fit)
 - [[Backblaze Integration]] — off-site backup plan (future)
 - [[Jellyfin]] — media server research brief
 - [[ARR-Stack]] — automated download stack research brief
@@ -159,3 +162,4 @@ The LLM inference fleet on the two hosts. Full index:
 
 - [AGENTS.md](../AGENTS.md) — repository rules
 - [docs/LLM/index.md](LLM/index.md) — the LLM fleet knowledge base
+- [dankware Configuration Knowledgebase](~/.pi/agent/docs/index.md) — the "root" level system knowlegebase