docs + guard: single 262k slot state, split-limits analysis, cache incident

- spec matrix + PP doc: production state = 1 slot @ 262144, split 0.53
  (34 blocks), KV 8192/8192, 3090 at 23460/24576. New 'Split limits
  (measured 2026-08-17)' section: 0.50/0.54/0.55 boundary data, the
  KV-per-device rounding rule (round(f x 66)), and why 35 blocks is
  unreachable (9-FA flip at f~0.538).
- PP doc: cache incident writeup - full Dankserver disk -> 0-byte cache
  entries -> corrupt weights -> degenerate output; fix + signature.
- deployment.md + AGENTS.md + index.md: numbers brought current.
- scripts/prune-rpc-cache.sh: cron guard capping the worker cache at
  40 GiB (oldest first) to prevent the disk-full recurrence.

AGENTS.md

@@ -5,9 +5,10 @@
 This project manages deployment scripts for the LLM inference fleet.
 Dankclaw runs a llama.cpp pipeline-parallel head for Qwen3.8-27B (unsloth
 UD-Q8_K_XL): MTP draft (bundled head, `--spec-draft-n-max 4`) over the
-`--spec-default` ngram-mod fallback, 2 parallel slots at 200704 context
-(pool 401400), tensors split 0.40/0.60 to the Dankserver RTX 3090
-`ggml-rpc` worker, head GPU side on ROCm0 (no `--device` flag), port 7770.
+`--spec-default` ngram-mod fallback, 1 slot at 262144 context (pool
+262144), tensors split 0.53/0.47 (34 of 65 blocks) to the Dankserver RTX
+3090 `ggml-rpc` worker, head GPU side on ROCm0 (no `--device` flag), port
+7770.
 The Dankclaw NPU endpoint (FastFlowLM, `frank-default-small`, port 52625)
 serves Qwen3.6-35B-A3B as registry tag `qwen3.6-moe:35b-a3b` at 262144 ctx
 (swapped in 2026-08-16; the old llama.cpp 35B service on Dankserver is