use Codex 5.3 to review template to spec

{{cookiecutter.project_slug}}/README.md

@@ -5,7 +5,7 @@
 ## Installation
 
 ```bash
-uv sync
+uv sync --frozen --group dev
 ```
 
 ## Usage
@@ -30,17 +30,31 @@ Override with:
 export {{ cookiecutter.package_name | upper }}_CONFIG=/path/to/config.toml
 ```
 
+Resolution order:
+1. `{{ cookiecutter.package_name | upper }}_CONFIG` explicit path (errors if missing)
+2. `~/.config/{{ cookiecutter.project_slug }}/config.toml` when present
+3. In-code defaults
+
+## Reproducible Workflow
+
+```bash
+uv lock
+uv sync --frozen --group dev
+uv run invoke lint
+uv run invoke test
+```
+
 ## Development
 
 ### Setup
 ```bash
-uv sync --group dev
+uv sync --frozen --group dev
 ```
 
 ### Code Quality
 ```bash
 uv run ruff check src tests
-uv run ruff format src tests
+uv run ruff format --check src tests
 uv run mypy src
 uv run invoke lint
 ```