docs(radiance): reference the engine's options, plugins and conversion

Nine pages under LLM/ document the upstream radiance engine at 8da043c:
- engine shape, plugin model, RAD2 container, ABI and environment
- every serve flag grouped with defaults and the law behind each knob
- the HTTP surface, request fields and refusal classes
- rad-convert, the recipe language, quantisers, imports, reuse, rad-export, KL scoring
- the (arch id, quant) family table and the recipe of record per model
- kernel/quantiser plugin authoring, encodings, build and checks
- architecture plugin authoring: declare, step, probe, lane and media rules
- rad-info/radbench/radtune and the shell harnesses
- the container contract, host prerequisites, readiness and restart triage

Also completes the dangling Related line on the frank-archon endpoint page.

serverAppConfigs-docs/index.md

@@ -162,6 +162,15 @@ is a locator: one row, one clause, no numbers.
 | [[PCIe Link and Atomics]] | Link probing, the streaming-versus-compute ceiling arithmetic, and the atomics wall that decides multi-GPU collectives. |
 | [[Quantization by Hardware Architecture]] | This page maps LLM quantization formats to the GPU and CPU architectures that support them. |
 | [[Quantization Production]] | Making a quantized payload here: the conversion recipe, the scoring gate, and the campaign ladder behind a shipped file. |
+| [[Radiance Architecture Plugins]] | Writing a radiance architecture plugin: declaring weights, buffers, KV groups and ops, then issuing the step. |
+| [[Radiance Conversion]] | Turning a checkpoint into a .rad container: rad-convert, the recipe language, quantisers, reuse and export. |
+| [[Radiance Engine]] | The radiance inference engine: its shape, plugin model, container format, and how the reference pages fit together. |
+| [[Radiance HTTP API]] | The HTTP surface radiance serves: endpoints, request fields, streaming, tools, and refusal rules. |
+| [[Radiance Model Families]] | Which radiance plugin claims which model family, and the conversion command and recipe of record for each. |
+| [[Radiance Operations]] | Running a radiance server: the container contract, host prerequisites, readiness, ledgers and safe restarts. |
+| [[Radiance Plugins]] | Writing radiance kernel and quantiser plugins: the ABI, kernel rows, hooks, encodings, and the build path. |
+| [[Radiance Serve Options]] | Every radiance serve flag grouped by task, with its default and the law that decides when to move it. |
+| [[Radiance Tools]] | The radiance inspection, measurement and tokeniser tools, with the flags and verdicts each one reports. |
 | [[RDNA4 MoE Expert Offload VRAM Budget]] | Expert-offload arithmetic on the RDNA4 fork: movable terms, the utilisation law, graph charge, ceilings, context ladder. |
 | [[Shared Memory Architecture Dankclaw]] | Dankclaw uses AMD Strix Halo APU with unified memory architecture. |