docs: rewrite getting-started as step-by-step guide

Replace the placeholder landing-page-style getting-started with a
comprehensive step-by-step guide that covers:

- Installation (pip, Homebrew, pre-commit, MCP)
- First check with zero configuration
- Configuration file setup (cchk.toml, priority, org-level)
- Pre-commit hooks setup
- CI/CD integration (GitHub Actions, GitLab CI, generic)
- AI agent / MCP setup
- Next steps reference

Fixes the biggest gap in the documentation site: a practical
onboarding path from zero to fully configured.

Author: shenxianpeng

docs/getting-started.md

@@ -1,51 +1,336 @@
 # Getting Started
 
-Welcome to commit-check! This guide will help you integrate commit-check into your workflow quickly and efficiently.
+Welcome to commit-check! This guide walks you from zero to enforcing commit
+standards in your project — no prior configuration needed.
 
 <!-- markdownlint-disable MD033 -->
 
-Select the method that best fits your development workflow:
+---
 
-<div class="grid cards" markdown>
+## 1. Install
 
-- :material-github: **GitHub Actions**
+Choose the installation method that fits your stack:
 
-    ---
+=== "pip (recommended)"
 
-    GitHub Action for automated commit-check in your workflows
+    ```bash
+    pip install commit-check
+    ```
 
-    **Perfect for:** CI/CD pipelines, automated PRs, team collaboration
+    Requires Python 3.10+. Works on Linux, macOS, and Windows.
 
-    [Get started with GitHub Actions →](https://github.com/commit-check/commit-check-action){ .md-button .md-button--primary }
+    Verify the installation:
 
-- :material-git: **Pre-commit Hooks**
+    ```bash
+    commit-check --version
+    # or its shorter alias
+    cchk --version
+    ```
 
-    ---
+=== "Homebrew (macOS)"
 
-    Pre-commit hooks for automated commit-check in your local development
+    ```bash
+    brew install commit-check
+    ```
 
-    **Perfect for:** Local development, enforcing commit standards before commits
+=== "pre-commit"
 
-    [Get started with pre-commit →](https://commit-check.github.io/commit-check/example.html#running-as-pre-commit-hook){ .md-button .md-button--primary }
+    No direct install needed — add to your `.pre-commit-config.yaml`:
 
-- :fontawesome-brands-python: **Command Line Interface (CLI)**
+    ```yaml
+    repos:
+      - repo: https://github.com/commit-check/commit-check
+        rev: v2.11.1
+        hooks:
+          - id: check-message
+          - id: check-branch
+    ```
 
-    ---
+    pre-commit will install commit-check automatically when you run
+    `pre-commit install --hook-type commit-msg`.
 
-    The core Python package powering commit-check-action behind the scenes
+=== "MCP Server (AI agents)"
 
-    **Perfect for:** Custom scripts, advanced workflows, and integration across different environments
+    AI coding agents (Claude Code, Cursor, Copilot) can use commit-check
+    without a direct Python install, via the MCP server:
 
-    [Get started with CLI →](https://commit-check.github.io/commit-check/){ .md-button .md-button--primary }
+    ```bash
+    # Run with uvx — no install needed
+    uvx commit-check-mcp
+    ```
 
-- :material-robot: **MCP Server**
+    See the [MCP Server docs](https://github.com/commit-check/commit-check-mcp)
+    for client-specific configuration instructions.
 
-    ---
+---
 
-    MCP server exposing commit-check validations as structured tools for AI coding agents
+## 2. Run Your First Check
 
-    **Perfect for:** Claude Code, Cursor, Copilot & any MCP-compatible AI agent
+Commit-check works **out of the box with zero configuration**. The default
+rules enforce:
 
-    [Get started with MCP →](https://github.com/commit-check/commit-check-mcp){ .md-button .md-button--primary }
+- [Conventional Commits](https://www.conventionalcommits.org/) for commit messages
+- [Conventional Branch](https://conventionalbranch.org/) for branch names
 
-</div>
+### Validate a commit message
+
+```bash
+# Pass a message via stdin
+echo "feat: add user authentication" | commit-check --message
+# Exit code: 0 (pass)
+
+echo "bad commit message" | commit-check --message
+# Exit code: 1 (fail) — shows error details and suggestion
+```
+
+### Validate from a file
+
+```bash
+# Pre-commit hooks pass the commit message file automatically
+commit-check --message .git/COMMIT_EDITMSG
+```
+
+### Validate the current branch
+
+```bash
+commit-check --branch
+```
+
+### Validate everything at once
+
+```bash
+commit-check --message --branch --author-name --author-email
+```
+
+### Quiet output for CI
+
+```bash
+# Compact mode: one [FAIL] line per failure, no ASCII art
+echo "bad message" | commit-check --message --compact
+# Output: [FAIL] message: bad message
+
+# Machine-readable JSON (great for automation and AI agents)
+echo "feat: add feature" | commit-check --message --format json
+```
+
+---
+
+## 3. Add a Configuration File
+
+To customize the rules for your project, create a `cchk.toml` in your
+repository root:
+
+```toml
+[commit]
+# Require imperative mood in subject lines
+subject_imperative = true
+
+# Enforce a 72-character subject limit
+subject_max_length = 72
+
+# Restrict allowed commit types
+allow_commit_types = ["feat", "fix", "docs", "refactor", "test", "chore"]
+
+# Bypass checks for bot authors
+ignore_authors = ["dependabot[bot]", "renovate[bot]"]
+
+# AI attribution policy: "ignore" (default) or "forbid"
+# "forbid" rejects commits co-authored by known AI coding agents
+ai_attribution = "forbid"
+
+[branch]
+# Require rebase onto main
+require_rebase_target = "main"
+```
+
+Run checks again — commit-check automatically discovers the config file:
+
+```bash
+commit-check --message --branch
+```
+
+> **Tip:** commit-check's TOML schema is published on
+> [SchemaStore](https://www.schemastore.org/), so editors like VS Code
+> (via the Even Better TOML extension) provide autocompletion and validation
+> for `cchk.toml` out of the box.
+
+### Configuration priority
+
+```
+CLI arguments  (highest priority)
+      ↑
+Environment variables  (CCHK_*)
+      ↑
+cchk.toml / commit-check.toml
+      ↑
+Built-in defaults  (lowest priority)
+```
+
+See the [configuration reference](https://commit-check.github.io/commit-check/configuration.html)
+for a complete list of all options.
+
+### Organization-wide config
+
+Share a base policy across all repos in your organization:
+
+```toml
+# .github/cchk.toml
+inherit_from = "github:my-org/.github:cchk.toml"
+
+[commit]
+subject_max_length = 72  # Override inherited value
+```
+
+---
+
+## 4. Set Up Pre-commit Hooks
+
+Commit-check provides five pre-commit hooks:
+
+| Hook ID | Stage | What it checks |
+|---------|-------|---------------|
+| `check-message` | `commit-msg` | Commit message follows Conventional Commits |
+| `check-branch` | `pre-commit` | Branch name follows Conventional Branch |
+| `check-author-name` | `pre-commit` | Author name format |
+| `check-author-email` | `pre-commit` | Author email format |
+| `check-no-force-push` | `pre-push` | Prevents force pushes |
+
+Add them to your `.pre-commit-config.yaml`:
+
+```yaml
+repos:
+  - repo: https://github.com/commit-check/commit-check
+    rev: v2.11.1
+    hooks:
+      - id: check-message
+      - id: check-branch
+      - id: check-author-name
+      - id: check-author-email
+
+  # Force push protection runs on pre-push (not pre-commit)
+  - repo: https://github.com/commit-check/commit-check
+    rev: v2.11.1
+    hooks:
+      - id: check-no-force-push
+        stages: [pre-push]
+```
+
+Install the hooks:
+
+```bash
+pre-commit install --hook-type commit-msg --hook-type pre-commit --hook-type pre-push
+```
+
+Now every commit, branch creation, and push is validated automatically.
+
+---
+
+## 5. Set Up CI/CD
+
+### GitHub Actions
+
+Add the [commit-check-action](https://github.com/commit-check/commit-check-action)
+to your workflow:
+
+```yaml
+name: Commit Check
+on: [push, pull_request]
+jobs:
+  commit-check:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write   # Required for PR comments
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          fetch-depth: 0      # Required for merge-base checks
+      - uses: commit-check/commit-check-action@v2
+        with:
+          message: true
+          branch: true
+          author-name: true
+          author-email: true
+          job-summary: true
+          pr-comments: ${{ github.event_name == 'pull_request' }}
+```
+
+### GitLab CI
+
+```yaml
+include:
+  - remote: https://raw.githubusercontent.com/commit-check/commit-check/main/examples/gitlab-ci.yml
+```
+
+### Other CI platforms
+
+commit-check is a standard Python CLI tool — it works anywhere Python runs.
+Set environment variables (`CCHK_*`) or check in a config file, then run
+`commit-check --message --branch` in your pipeline step.
+
+---
+
+## 6. Set Up for AI Coding Agents (MCP)
+
+If your team uses AI coding agents (Claude Code, Cursor, Copilot, etc.),
+commit-check helps enforce commit standards even on AI-generated commits.
+
+### Claude Desktop
+
+```json
+{
+  "mcpServers": {
+    "commit-check": {
+      "command": "uvx",
+      "args": ["commit-check-mcp"]
+    }
+  }
+}
+```
+
+### Claude Code CLI
+
+Add to your project's `.claude/settings.local.json`:
+
+```json
+{
+  "mcpServers": {
+    "commit-check": {
+      "command": "uvx",
+      "args": ["commit-check-mcp"]
+    }
+  }
+}
+```
+
+### AI Attribution Policy
+
+Use the `ai_attribution` config option to control AI-assisted commits:
+
+```toml
+[commit]
+# "ignore" (default) — AI co-authored commits are allowed
+# "forbid"          — rejects commits with known AI tool signatures
+ai_attribution = "forbid"
+```
+
+When set to `forbid`, commit-check detects signatures from 10+ AI coding
+tools (Claude Code, GitHub Copilot, Cursor, Codex, and more) and rejects
+commits that carry them.
+
+See the [MCP Server README](https://github.com/commit-check/commit-check-mcp)
+for all supported clients and configuration options.
+
+---
+
+## Next Steps
+
+| Topic | Where to go |
+|-------|-------------|
+| Complete configuration reference | [Configuration docs](https://commit-check.github.io/commit-check/configuration.html) |
+| In-depth examples | [Examples page](https://commit-check.github.io/commit-check/example.html) |
+| Python API (for automation) | [API reference](commit_check.api) in the Python package |
+| Migrate from v1 (YAML) to v2 (TOML) | [Migration guide](https://commit-check.github.io/commit-check/migration.html) |
+| GitHub Action details | [commit-check-action](https://github.com/commit-check/commit-check-action) |
+| AI agent integration | [commit-check-mcp](https://github.com/commit-check/commit-check-mcp) |
+| Report a bug or request a feature | [GitHub Issues](https://github.com/commit-check/commit-check/issues) |