docs: update references from "AI coding agent" to "AI coding tool"

Author: MUHAMMEDHAFEEZ

CONTRIBUTING.md

@@ -11,7 +11,7 @@ These are one time installations required to be able to test your changes locall
 1. Install [Python 3.11+](https://www.python.org/downloads/)
 1. Install [uv](https://docs.astral.sh/uv/) for package management
 1. Install [Git](https://git-scm.com/downloads)
-1. Have an [AI coding agent available](README.md#-supported-ai-agents)
+1. Have an [AI coding tool available](README.md#-supported-ai-tools)
 
 <details>
 <summary><b>💡 Hint if you are using <code>VSCode</code> or <code>GitHub Codespaces</code> as your IDE</b></summary>

README.md

@@ -517,7 +517,7 @@ Our research and experimentation focus on:
 ## 🔧 Prerequisites
 
 - **Linux/macOS/Windows**
-- [Supported](#-supported-ai-agents) AI coding agent.
+- [Supported](#-supported-ai-tools) AI coding tool.
 - [uv](https://docs.astral.sh/uv/) for package management
 - [Python 3.11+](https://www.python.org/downloads/)
 - [Git](https://git-scm.com/downloads)

docs/upgrade.md

@@ -9,7 +9,7 @@
 | What to Upgrade | Command | When to Use |
 |----------------|---------|-------------|
 | **CLI Tool Only** | `uv tool install specify-cli --force --from git+https://github.com/github/spec-kit.git@vX.Y.Z` | Get latest CLI features without touching project files |
-| **Project Files** | `specify init --here --force --ai <your-agent>` | Update slash commands, templates, and scripts in your project |
+| **Project Files** | `specify init --here --force --ai <your-tool>` | Update slash commands, templates, and scripts in your project |
 | **Both** | Run CLI upgrade, then project update | Recommended for major version updates |
 
 ---
@@ -73,7 +73,7 @@ The `specs/` directory is completely excluded from template packages and will ne
 Run this inside your project directory:
 
 ```bash
-specify init --here --force --ai <your-agent>
+specify init --here --force --ai <your-tool>
 ```
 
 Replace `<your-agent>` with your AI assistant. Refer to this list of [Supported AI Tools](../README.md#-supported-ai-tools)