docs: passwordless restart helpers, parallel-streams incident, MTP drafter findings

- deployment.md: document the sudoers NOPASSWD restart helpers on both
  targets, the exact-argument matching quirk, and the 2026-08-13
  'premature job release' investigation (server never preempts; aborts
  were client-side; Dankserver crashed twice under researcher load).
- DFlash/DSpark doc: MTP requires MTP tensors in the target GGUF; the
  HauhauCS Qwen3.6-27B GGUF has none (verified tensor listing); MTP-only
  draft GGUFs (a4lg/lym00) pair via --spec-draft-model; flag rename
  --spec-type mtp -> draft-mtp in b9180.
- AGENTS.md: operational quirks for the helpers, journal abort-vs-release
  signature, and the Dankserver cublasSgemm crash signature.

AGENTS.md

@@ -83,9 +83,12 @@ graph TD
 ### Operational quirks
 
 - `sudo` on both boxes needs a tty. The remote sudo steps in `deploy.sh` fail non-interactively. Use `echo '<password>' | sudo -S <command>`.
+- Passwordless restarts: each target has a root-owned helper (`/usr/local/sbin/frank-restart-large.sh` on Dankclaw, `frank-restart-small.sh` on Dankserver) and a sudoers NOPASSWD drop-in (`/etc/sudoers.d/frank-*`). `deploy.sh` prefers the helper. The sudoers rules match commands exactly: no extra arguments (for example, `--no-pager` breaks the `systemctl status` rule). See [docs/deployment.md](docs/deployment.md).
 - Never run `pkill -f` with a pattern that appears in your own command line. It kills your ssh session. Use `pkill -x <exact-name>`.
 - Model load is slow: about 3 minutes warm, more than 8 minutes cold. Health returns `503 Loading model` the whole time. That is normal. Do not kill the process.
 - Page-cache state confounds crash tests. Cold-cache loads are slow and survive. Warm-cache loads crash fast. Control for it when testing. `deploy.sh` drops caches on Dankclaw before restart (see `DROP_CACHES`); manual restarts must run `sync && echo 3 | sudo tee /proc/sys/vm/drop_caches` first.
+- A client abort and a server release look different in the journal. A client abort logs `W srv stop: cancel task, id_task = N`. A natural stop (EOS or limit) logs only `slot release` with `truncated = 0`. The server never preempts a running generation; when all slots are busy, new tasks defer into a queue. See the 2026-08-13 incident in [docs/deployment.md](docs/deployment.md).
+- Dankserver crash signature under parallel load: `CUDA error: an unsupported value or parameter was passed to the function` in `cublasSgemm_v2` at `ggml-cuda.cu:1541`, then `status=6/ABRT`, then `503 Loading model` for ~5 minutes. Happened twice on 2026-08-13 under a 5-researcher subagent storm (llama.cpp b10121, driver 595.84). Root cause not yet determined; do not confuse it with speculative decoding.
 
 ### Dankclaw memory model