docs: the hf command as the manual way to fetch model files (DETAILS.md)

A short section next to the Linux setup: what Strata's own downloader does, the measured speeds (anonymous, 16-24 MB/s whatever the method), and the manual route
with `hf download` and `--gguf-dir`, which setup already supports (checks the SHA-256, never deletes a file in your own folder). No code change.

docs/DETAILS.md

@@ -205,6 +205,25 @@ request: [SOURCE_INSTALL.md](SOURCE_INSTALL.md#build-from-git-on-linux-to-try-a-
 
 ---
 
+### Downloading the model files yourself
+
+Setup downloads the model files over 16 connections (`STRATA_DL_CONNECTIONS` 1 to 32), resumes a stopped download, and checks every file's SHA-256 against the
+pinned value. Measured from two computers (a home PC and a server in China), anonymous downloads from Hugging Face ran at 16 to 19 MB/s whatever the connection count (one
+stream 7 MB/s, 16 connections 17, 32 connections 19). Hugging Face's own `hf` command with its Xet backend gave 16 to 24 MB/s anonymously in the same test, so it is
+not faster by itself. Hugging Face limits anonymous requests per IP address and says a login (a token of your own account) raises the limits, so if the download is slow
+you can fetch the file with the `hf` command, optionally after `hf auth login`, and give the folder to setup:
+
+```bash
+uvx hf auth login            # optional: your own Hugging Face account; Strata does not read or send this token
+uvx hf download agentionai/Qwen3.8-Flash-Next-Gyro-GGUF Qwen3.8-Flash-Next-Gyro-S-TQ1_0.gguf \
+    --revision 1ada08422e404aca51ab9df665f089f34c419c6b --local-dir /data/gyro-s
+./setup.sh --gguf-dir /data/gyro-s       # Windows: SETUP.bat --gguf-dir D:\gyro-s
+```
+
+Use the file names and the revision setup shows for your model (the revision above is the one this version pins for Gyro-S: another version of Strata may pin another).
+Keep the file's original name. Setup finds the files in `--gguf-dir`, checks their SHA-256 and does not download them again; a file that does not match the published one is
+reported and, for files in your own folder, never deleted. Without `uvx`, `pip install -U huggingface_hub` gives the same `hf` command.
+
 ## Memory modes
 
 ### KV cache