docs: ✏️ update CLI usage and configuration sections

docs/src/content/docs/getting-started/configuration.mdx

@@ -64,6 +64,13 @@ GENAISCRIPT_MODEL_SMALL="azure_serverless:..."
 GENAISCRIPT_MODEL_VISION="azure_serverless:..."
 ```
 
+You can also configure the default aliases for a given LLM provider by using the `--provider` argument in the CLI.
+The default are documented in this page and printed to the console output.
+
+```sh
+genaiscript run ... --provider anthropic
+```
+
 ### Model aliases
 
 In fact, you can define any alias for your model (only alphanumeric characters are allowed)

docs/src/content/docs/reference/cli/run.mdx

@@ -50,11 +50,21 @@ Exclude files ignored by the `.gitignore` file at the workspace root.
 npx genaiscript run <script> <files> --exclude-git-ignore
 ```
 
-## Output
+## Configuration
+
+### --model ...
+
+Configure the default or `large` model alias
+
+## --provider ...
 
-### --prompt
+Loads a set of model aliases for the given LLM provider.
 
-Skips the LLM invocation and only prints the expanded system and user chat messages.
+### --vars name=value name2=value2 ...
+
+Populate values in the `env.vars` map that can be used when running the prompt.
+
+## Output
 
 ### --out &lt;file|directory&gt;
 
@@ -78,10 +88,6 @@ Output the entire response as JSON to the stdout.
 
 Output the entire response as YAML to the stdout.
 
-### --vars name=value name2=value2 ...
-
-Populate values in the `env.vars` map that can be used when running the prompt.
-
 ### --out-trace &lt;file&gt;
 
 Save the markdown trace to the specified file.

docs/src/content/docs/reference/scripts/model-aliases.mdx

@@ -89,3 +89,10 @@ The following aliases are also set so that you can override LLMs used by GenAISc
 
 - `agent`: `large`. Model used by the Agent LLM.
 - `memory`: `small`. Moel used by the agent short term memory.
+
+The default aliases for a given provider can be loaded using the `provider` option in the [cli](/genaiscript/reference/cli/run).
+
+```sh
+genaiscript run --provider anthropic
+```
+