docs: Improve README and rename AGENTS.md to CONTRIBUTING.md

Restructures the README for clarity, providing separate instructions for users and developers.

Renames AGENTS.md to the standard CONTRIBUTING.md to better signal its purpose for potential contributors.

Author: aureliuscanon

AGENTS.md CONTRIBUTING.mdAGENTS.md renamed to CONTRIBUTING.md

@@ -13,14 +13,29 @@ A privacy-aware linter for Python projects, designed to catch accidental leaks o
 - **CI/CD Friendly**: Exits with a non-zero code only on `ERROR` findings, allowing warnings to be reviewed without blocking development.
 - **Extensible**: Powered by a combination of custom AST checks and a Semgrep rule engine.
 
-## Usage
+## Installation
+
+It is highly recommended to install `privlog` within a project's virtual environment to avoid dependency conflicts.
 
-First, install the tool in your project's virtual environment:
+**Recommended (Virtual Environment):**
 ```sh
-pip install -e .
+# 1. Create and activate a virtual environment in your project directory
+python -m venv .venv
+source .venv/bin/activate  # On Windows, use: .venv\Scripts\activate
+
+# 2. Install privlog
+pip install privlog
 ```
 
-To run the checks, use the `privlog` command.
+**Global Installation:**
+*While not recommended for most workflows, you can also install it globally:*
+```sh
+pip install privlog
+```
+
+## Usage
+
+Once installed, run the `privlog` command on your project directory.
 
 ### Default (Errors Only)
 
@@ -44,3 +59,21 @@ To see both `ERROR`s and `WARNING`s, use the `-w` or `--warnings` flag.
 privlog -w /path/to/your/project
 ```
 This will display all findings, color-coded by severity, but will still only fail the build if `ERROR`s are present.
+
+---
+
+## For Developers
+
+To set up a development environment to contribute to `privlog`:
+```sh
+# 1. Clone the repository and navigate into the directory
+git clone https://github.com/privlog-dev/privlog.git
+cd privlog
+
+# 2. Create and activate a virtual environment
+python -m venv .venv
+source .venv/bin/activate
+
+# 3. Install the tool in editable mode with development dependencies
+pip install -e .
+```