docs: Move .env info earlier in README

Move notes about local development configuration overrides (using
a `.env` file) and the XDG Base Directory link to immediately
follow the general configuration setup section. This ensures
crucial setup information is not buried lower in the document.

Author: rm-hull

README.md

@@ -22,6 +22,10 @@ go install github.com/rm-hull/git-commit-summary
 
 You can configure the LLM provider by setting the `LLM_PROVIDER` environment variable. The supported providers are `google` (default) and `openai`.
 
+For local development or repository-specific overrides, you can still create a `.env` file in your git repository root.
+
+For more information on the XDG Base Directory Specification, see: [https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html](https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html)
+
 #### Google
 
 Add your Gemini API key to the `config.env` file:
@@ -52,10 +56,6 @@ OPENAI_BASE_URL="http://localhost:8080/v1"
 OPENAI_MODEL="Meta-Llama-3.1-8B-Instruct-Q4_K_M"
 ```
 
-For local development or repository-specific overrides, you can still create a `.env` file in your git repository root.
-
-For more information on the XDG Base Directory Specification, see: [https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html](https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html)
-
 ## Usage
 
 Once installed, check that the executable is on the $PATH, with `git-commit-summary --version`. Then, as part of your development workflow