docs: update README and examples for v1.0.0

- Rewrite README with all new endpoints and current model names
- Add available models table with constructors
- Add FIM and OCR examples
- Update all examples for string-based Model type
- Update streaming example for Option<String> delta content
- Use serde_json::json!() for tool schemas in examples
- Add .envrc to .gitignore

examples/embeddings_async.rs

@@ -1,11 +1,11 @@
-use mistralai_client::v1::{client::Client, constants::EmbedModel};
+use mistralai_client::v1::{client::Client, constants::Model};
 
 #[tokio::main]
 async fn main() {
     // This example suppose you have set the `MISTRAL_API_KEY` environment variable.
     let client: Client = Client::new(None, None, None, None).unwrap();
 
-    let model = EmbedModel::MistralEmbed;
+    let model = Model::mistral_embed();
     let input = vec!["Embed this sentence.", "As well as this one."]
         .iter()
         .map(|s| s.to_string())
@@ -17,5 +17,4 @@ async fn main() {
         .await
         .unwrap();
     println!("First Embedding: {:?}", response.data[0]);
-    // => "First Embedding: {...}"
 }