data: add trusted reference fingerprint for DeepSeek-V4.1-Flash (official api.deepseek.com)

Collected with this tool against https://api.deepseek.com/v1, model id
deepseek-flash (API name: DeepSeek-V4.1-Flash), standard preset (8 cells x 25
samples), protocol one-token/v1, reasoning disabled via the openai-effort
adapter. 200/200 valid, 0 errors.

Unlike the bundled Zenodo samples, this reference is protocol-matched to the
package battery, so compare()/verify() against it is a direct comparison.

data/references/README.md

@@ -0,0 +1,46 @@
+# Reference fingerprints (trusted, collected with this tool)
+
+These are **first-party** references — collected by `llm-fingerprint-detector`
+itself against a provider you trust, using the package's own `one-token/v1`
+battery. Unlike `../reference-fingerprints.sample.json` (Zenodo paper data,
+`bruckner-zenodo-2026` protocol), these are protocol-matched, so a
+`compare()` against them is a direct, non-indicative comparison.
+
+| file | model id | provider | collected | protocol | battery |
+|---|---|---|---|---|---|
+| `deepseek-v4.1-flash.official.json` | `deepseek-flash` | api.deepseek.com (official) | 2026-10-04 | `one-token/v1` | 8 cells × 25 samples |
+
+## `deepseek-v4.1-flash.official.json`
+
+- **Endpoint:** `https://api.deepseek.com/v1`
+- **Model id requested:** `deepseek-flash` (API-reported name: `DeepSeek-V4.1-Flash`)
+- **Collected:** 2026-10-04, standard preset, `temperature=1`, reasoning disabled
+  via the `openai-effort` adapter
+- **Result:** 200/200 samples valid, 0 errors, `postReasoning: false`
+- **Use it to verify a reseller:** a reseller advertising `deepseek-v4.1-flash`
+  (or `deepseek-flash`) should land in the *match* band against this file.
+
+```bash
+# verify a suspect endpoint against this trusted reference
+llm-fingerprint verify \
+  --base-url https://reseller.example.com/v1 \
+  --model deepseek-v4.1-flash \
+  --reference data/references/deepseek-v4.1-flash.official.json
+```
+
+### The official fingerprint's most discriminative cells
+
+| cell | official DeepSeek-V4.1-Flash | notes |
+|---|---|---|
+| `random-number-1-100:en` | `42` ×19 / 25 | overwhelming 42 bias |
+| `random-number-1-100:zh` | `42` ×14 / 25 | same bias, Chinese |
+| `random-color:en` | `blue` ×25 / 25 | fully deterministic |
+| `coin-flip:en` | `heads` ×25 / 25 | fully deterministic |
+| `random-number-1-10:en` | `7` ×23 / 25 | near-deterministic |
+| `random-letter:en` | `q` ×18 / 25 | q ≫ k ≫ g |
+| `random-color:zh` | `蓝` ×20 / 25 | 蓝 ≫ 紫, 橙 |
+| `random-animal:en` | `elephant` ×11, `cat` ×9 | elephant dominates |
+
+**Caveat:** references drift as providers ship model updates. Re-collect if the
+file is more than ~1–2 months old, or if a verification you trust starts
+returning `uncertain`.