docs: improve textlint-website-generator README with comprehensive usage instructions (#114)

- Add clear overview and features section
- Expand usage examples from basic to advanced
- Document all CLI options with detailed explanations
- Add 'How It Works' technical explanation
- Include configuration details for package.json and .textlintrc
- Document project structure for developers
- Add integration notes for textlint-editor browser extension

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

Author: azu

packages/@textlint/website-generator/README.md

@@ -1,6 +1,19 @@
 # @textlint/website-generator
 
-Website generator using @textlint/script-compiler
+A website generator that creates a standalone web application for textlint, allowing users to lint text directly in the browser using your configured textlint rules.
+
+## Overview
+
+`@textlint/website-generator` compiles your textlint configuration and rules into a web worker script and generates a complete website with an interactive text editor. This enables users to experience your textlint rules without any installation.
+
+## Features
+
+- Generates a standalone website with textlint functionality
+- Compiles textlint rules to run in web workers
+- Creates an interactive text editor with real-time linting
+- Supports custom styling with title and placeholder text
+- Works with existing `.textlintrc` configuration files
+- Automatically infers metadata from `package.json`
 
 ## Install
 
@@ -10,6 +23,16 @@ Install with [npm](https://www.npmjs.com/):
 
 ## Usage
 
+### Basic Usage
+
+Generate a website using your existing `.textlintrc` configuration:
+
+```bash
+textlint-website-generator --output-dir ./dist
+```
+
+### Command Line Options
+
     Usage
       $ textlint-website-generator 
 
@@ -18,13 +41,102 @@ Install with [npm](https://www.npmjs.com/):
       --placeholder               [String] Placeholder text in generated website
       --cwd                       current working directory
       --textlintrc                [path:String] path to .textlintrc file. Default: load .textlintrc.{json,yaml,js}
-      --output-dir                [path:String] output file path that is written of reported result.
-      --metadataName             [String] generated script name
-      --metadataNamespace        [String] generated script namespace
+      --output-dir                [path:String] output directory for generated website files (required)
+
+    Metadata Options
+      Metadata is inferred from package.json by default.
+      If you want to set metadata manually, use these flags:
+    
+      --metadataName              [String] generated script name
+      --metadataNamespace         [String] generated script namespace (URL)
+      --metadataHomepage          [String] generated script homepage URL
+      --metadataVersion           [String] generated script version
 
     Examples
-      $ textlint-website-generator --output-dir ./dist --metadataName "script name" --metadataNamespace "https://example.com"
-      $ textlint-website-generator --output-dir ./dist --metadataName "script name" --metadataNamespace "https://example.com" --title "rule tester" --placeholder "default text" 
+      # Basic usage with package.json metadata
+      $ textlint-website-generator --output-dir ./dist
+      
+      # Custom title and placeholder
+      $ textlint-website-generator --output-dir ./dist --title "My Textlint Rules" --placeholder "Type or paste your text here..."
+      
+      # Manual metadata configuration
+      $ textlint-website-generator --output-dir ./dist --metadataName "my-rules" --metadataNamespace "https://example.com"
+      
+      # Full customization
+      $ textlint-website-generator --output-dir ./dist --metadataName "script name" --metadataNamespace "https://example.com" --title "rule tester" --placeholder "default text"
+
+## How It Works
+
+1. **Compilation**: The generator uses `@textlint/script-compiler` to compile your textlint configuration and rules into a web worker script (`textlint-worker.js`)
+
+2. **Template Generation**: It creates an HTML page with:
+   - An interactive textarea for text input
+   - Integration with `textchecker-element` for real-time linting
+   - Support for the textlint-editor browser extension
+
+3. **Output**: The generator produces:
+   - `index.html` - The main webpage
+   - `textlint-worker.js` - Compiled textlint rules as a web worker
+   - `textchecker-element.esm.js` - UI component for text checking
+
+## Configuration
+
+### Using package.json
+
+By default, the generator reads metadata from your `package.json`:
+
+```json
+{
+  "name": "my-textlint-rules",
+  "version": "1.0.0",
+  "homepage": "https://github.com/username/my-textlint-rules"
+}
+```
+
+### Using .textlintrc
+
+The generator automatically loads your textlint configuration from:
+- `.textlintrc`
+- `.textlintrc.json`
+- `.textlintrc.yaml`
+- `.textlintrc.js`
+
+Or specify a custom path:
+
+```bash
+textlint-website-generator --textlintrc ./config/.textlintrc.json --output-dir ./dist
+```
+
+## Development Workflow
+
+### Building the Template
+
+The package includes a script to generate the template files:
+
+```bash
+npm run generate-template
+```
+
+This runs before packaging to ensure the latest template is included.
+
+### Project Structure
+
+```
+packages/@textlint/website-generator/
+├── bin/
+│   └── cmd.js              # CLI entry point
+├── src/
+│   ├── cli.ts              # CLI implementation
+│   └── website-generator.ts # Core generator logic
+├── template/
+│   ├── index.html          # HTML template
+│   └── textchecker-element.esm.js # UI component
+└── lib/                    # Compiled JavaScript output
+```
+
+## Integration with textlint-editor
+
+The generated website can work with the [textlint-editor browser extension](https://github.com/textlint/editor) for enhanced functionality. Users can install custom rule scripts using the "Install" button on the generated page. 
 
 ## Changelog