common: support remote preset (#18520)

* arg: support remote preset

* proof reading

* allow one HF repo to point to multiple HF repos

* docs: mention about multiple GGUF use case

* correct clean_file_name

* download: also return HTTP status code

* fix case with cache file used

* fix --offline option

docs/preset.md

@@ -0,0 +1,60 @@
+# llama.cpp INI Presets
+
+## Introduction
+
+The INI preset feature, introduced in [PR#17859](https://github.com/ggml-org/llama.cpp/pull/17859), allows users to create reusable and shareable parameter configurations for llama.cpp.
+
+### Using Presets with the Server
+
+When running multiple models on the server (router mode), INI preset files can be used to configure model-specific parameters. Please refer to the [server documentation](../tools/server/README.md) for more details.
+
+### Using a Remote Preset
+
+> [!NOTE]
+>
+> This feature is currently only supported via the `-hf` option.
+
+For GGUF models hosted on Hugging Face, you can include a `preset.ini` file in the root directory of the repository to define specific configurations for that model.
+
+Example:
+
+```ini
+hf-repo-draft = username/my-draft-model-GGUF
+temp = 0.5
+top-k = 20
+top-p = 0.95
+```
+
+For security reasons, only certain options are allowed. Please refer to [preset.cpp](../common/preset.cpp) for the complete list of permitted options.
+
+Example usage:
+
+Assuming your repository `username/my-model-with-preset` contains a `preset.ini` with the configuration above:
+
+```sh
+llama-cli -hf username/my-model-with-preset
+
+# This is equivalent to:
+llama-cli -hf username/my-model-with-preset \
+  --hf-repo-draft username/my-draft-model-GGUF \
+  --temp 0.5 \
+  --top-k 20 \
+  --top-p 0.95
+```
+
+You can also override preset arguments by specifying them on the command line:
+
+```sh
+# Force temp = 0.1, overriding the preset value
+llama-cli -hf username/my-model-with-preset --temp 0.1
+```
+
+If you want to define multiple preset configurations for one or more GGUF models, you can create a blank HF repo for each preset. Each HF repo should contain a `preset.ini` file that references the actual model(s):
+
+```ini
+hf-repo = user/my-model-main
+hf-repo-draft = user/my-model-draft
+temp = 0.8
+ctx-size = 1024
+; (and other configurations)
+```