Add DeepSeek-V4-Flash-0731 DwarfStar-4 (IQ2XXS) guide + card

[TheTom]

Adds an offlabel operating guide + card for DeepSeek-V4-Flash-0731 on DwarfStar-4 (antirez/ds4), the IQ2XXS asymmetric quant. This is a distinct stack from our existing Config-I GGUF guide (different quant, different engine), so it gets its own guide.

What this is: an independent replication of a viral DGX-Spark deployment writeup, plus a 174-call Laguna-depth behavioral battery. Single tester, one day, one stack (status: EARLY).

Corrects the record

The writeup describes this as "685B params, 64 routed experts." We parsed the GGUF header directly: it is deepseek4, 256 experts, 6 active + 1 shared, ~21B active. The 685B/64-expert figure is DeepSeek-V3/R1-class numbers attached by association. Every throughput number should be read as a ~21B-active MoE.

Validated on-box (nothing on the card is unmeasured)

• Decode 21-26 tok/s, DSpark accept 29-87%, prefill ~1000 tok/s at depth.
• TTFT 170-320ms (writeup claimed 3-16s).
• Reasoning 8/8, tool calling 3/3.
• Concurrency to 24 sessions at full 262K: 100% success, peak ~78 tok/s aggregate at max_seq=21. Busts the writeup's "only 2 concurrent" claim.
• Includes HF/GitHub links (quant, drafter, engine fork, installer) and single + parallel run recipes.

Behavioral (all n stated, stack-labeled)

• Does not reproduce the repetition-loop our Config-I GGUF hit on the same prompt.
• Strong: harmful refusals 12/12, authority-pressure 9/9, no fabrication 9/9, tool-injection resisted 3/3, format 9/9, long-output coherent to 2000 tok.
• Signature bug: ~20-27% content-dump-into-content on reflective/low-budget prompts (empties reasoning_content, hits length, never answers). Fixed by a concise system prompt (4/4 → 0/4). enable_thinking:false backfires. Retry heuristic documented.
• Safety caveat: a fiction-framing jailbreak partially succeeded (produced real device-construction detail) where DAN + prefix-injection were cleanly refused.

Lint (scripts/check_guides.py) passes: frontmatter, required keys, no em/en-dashes.