* refactor: move thinking toggle to runtime settings for per-message control
Replaces the static `reasoning_budget` config with a dynamic `enable_thinking` flag under `chat_template_kwargs`, allowing models like Jan-nano and Qwen3 to enable/disable thinking behavior at runtime, even mid-conversation.
Requires UI update
* remove engine argument
Adds a new configuration option `chat_template` to the Llama.cpp extension, allowing users to define a custom Jinja chat template for the model.
The template can be provided via a new input field in the settings, and if set, it will be passed to the Llama.cpp backend using the `--chat-template` argument. This enhances flexibility for users who require specific chat formatting beyond the GGUF default.
The `chat_template` is added to the `LlamacppConfig` type and conditionally pushed to the command arguments if it's provided. The placeholder text provides an example of a Jinja template structure.
* wip
* update
* add download logic
* add decompress. support delete file
* download backend upon selecting setting
* add some logging and nootes
* add note on race condition
* remove then catch
* default to none backend. only download if it's not installed
* merge version and backend. fetch version from GH
* restrict scope of output_dir
* add note on unpack
