docs(readme): enhance documentation with installation, workflow and configuration details

- Add installation instructions with marketplace link and CLI command
- Expand typical workflow section with keyboard shortcuts
- Add detailed commands section with keyboard shortcuts
- Include comprehensive configuration options with defaults and ranges
- Add error handling section with categorized error scenarios
- Update development section with clearer instructions
- Add hyperlinks for external resources
- Improve formatting and readability with keyboard shortcut styling

Author: tsdevau

README.md

@@ -1,8 +1,8 @@
 # Diff Commit
 
-Diff Commit is a VSCode extension that helps you generate commit messages following the conventional commits specification using Anthropic's AI models like Claude 3.5 Sonnet. Commit messages are generated using the diff of staged changes and entered directly into the SCM message input.
+Diff Commit is a VSCode extension that helps you generate commit messages following the conventional commits specification using Anthropic's AI models like Claude 3.5 Sonnet. Commit messages are generated using the diff of staged changes and entered directly into the SCM message input or previewed in a new editor window.
 
-The generated commit messages are compatible with googleapis/release-please and other tools that use conventional commits.
+The generated commit messages are compatible with [googleapis/release-please](https://github.com/googleapis/release-please) and other tools that use conventional commits.
 
 ## Features
 
@@ -15,68 +15,101 @@ The generated commit messages are compatible with googleapis/release-please and
 
 - VSCode 1.9.4 or higher
 - Git installed and configured in your workspace
-- An Anthropic API key for accessing Claude 3.5 AI
+- An [Anthropic API key](https://console.anthropic.com/settings/keys)
 
-## Usage
+## Installation
 
-1. Stage your changes in Git
-2. Open the Command Palette (Cmd/Ctrl + Shift + P)
-3. Run the command: "DiffCommit :: Generate Commit Message"
-4. Enter your Anthropic API key when prompted for message generation
+Install the extension directly from the [Visual Studio Code Marketplace](https://marketplace.visualstudio.com/items?itemName=tpsTech.diff-commit) or:
+
+1. Open VSCode
+2. Press <kbd>Cmd</kbd>/<kbd>Ctrl</kbd> + <kbd>P</kbd>
+3. Type `ext install tpsTech.diff-commit`
+
+## Typical Workflow
+
+1. Stage your changes in Source Control
+2. Open the Command Palette (<kbd>Cmd</kbd>/<kbd>Ctrl</kbd> + <kbd>Shift</kbd> + <kbd>P</kbd>)
+3. Run the command: "DiffCommit: Generate Commit Message" (<kbd>Cmd</kbd>/<kbd>Ctrl</kbd> + <kbd>K</kbd> then <kbd>Cmd</kbd>/<kbd>Ctrl</kbd> + <kbd>G</kbd>)
+4. Enter your Anthropic API key when prompted (_first time only_)
 5. Review the generated commit message in the Source Control message input
 6. Edit the commit message if necessary
 7. Click 'Commit' to commit the changes with the generated message
 
-## Configuration
+## Commands
 
-The extension provides the following settings:
+Access DiffCommit commands from the Command Palette (<kbd>Cmd</kbd>/<kbd>Ctrl</kbd> + <kbd>Shift</kbd> + <kbd>P</kbd>) or using the keyboard shortcuts:
 
-- `diffCommit.model`: The Anthropic AI model to use for generating commit messages. (Default: "claude-3-5-sonnet-20241022", Options: "claude-3-5-sonnet-latest", "claude-3-opus-latest", "claude-3-sonnet-20240229", "claude-3-haiku-20240307")
-- `diffCommit.maxTokens`: Maximum number of tokens to generate in the response. Higher values allow for longer commit messages but use more API tokens. (Default: 1024, Range: 1-8192)
-- `diffCommit.temperature`: Controls randomness in the response. Lower values (like 0.4) produce more focused and consistent commit messages, while higher values introduce more variety. (Default: 0.4, Range: 0-1)
+- `DiffCommit: Generate Commit Message`: Generate a commit message for staged changes and enter it in the Source Control message input
+  - macOS: <kbd>Cmd</kbd> + <kbd>K</kbd> then <kbd>Cmd</kbd> + <kbd>G</kbd>
+  - Windows/Linux: <kbd>Ctrl</kbd> + <kbd>K</kbd> then <kbd>Ctrl</kbd> + <kbd>G</kbd>
+- `DiffCommit: Preview Commit Message`: Generate a commit message for staged changes and preview it in an editor window
+  - macOS: <kbd>Cmd</kbd> + <kbd>K</kbd> then <kbd>Cmd</kbd> + <kbd>P</kbd>
+  - Windows/Linux: <kbd>Ctrl</kbd> + <kbd>K</kbd> then <kbd>Ctrl</kbd> + <kbd>P</kbd>
+- `DiffCommit: Update API Key`: Update the Anthropic API key used for API access
+- `DiffCommit: Delete API Key`: Remove the stored Anthropic API key
+
+## Configuration
+
+This extension provides the following settings:
+
+- `diffCommit.allowedTypes`: List of allowed commit types. If provided, this replaces the default options.
+  - Default: [ "feat", "fix", "refactor", "chore", "docs", "style", "test", "perf", "ci" ]
+  - Options: Array<string>
+- `diffCommit.customInstructions`: Add additional custom instructions to the commit generation prompt. Useful for providing context or specific requirements like 'Use Australian English spelling'.
+  - Default: ""
+- `diffCommit.model`: The Anthropic AI model to use for generating commit messages.
+  - Default: "claude-3-5-sonnet-latest"
+  - Options: "claude-3-opus-latest" | "claude-3-sonnet-20240229" | "claude-3-haiku-20240307"
+- `diffCommit.maxTokens`: Maximum number of tokens to generate in the response. Higher values allow for longer commit messages but use more API tokens.
+  - Default: 1024
+  - Range: 1 - 8192
+- `diffCommit.temperature`: Controls randomness in the response. Lower values (like 0.4) produce more focused and consistent commit messages, while higher values introduce more variety.
+  - Default: 0.4
+  - Range: 0 - 1
 
 ## Error Handling
 
-Diff Commit includes comprehensive error handling to provide clear feedback and assist in troubleshooting. Here are some common error scenarios and their meanings:
+Diff Commit includes comprehensive error handling to provide clear feedback and assist in troubleshooting. Here are the common error scenarios you might encounter:
+
+### Git Related
+
+- Git extension not found in VSCode
+- No Git repository found in the current workspace
+- No workspace folder found
+- No staged changes detected
 
-- `GIT_EXTENSION_NOT_FOUND`: The VSCode Git extension is not installed or activated
-- `NO_GIT_REPO`: No Git repository was found in the current workspace
-- `NO_STAGED_CHANGES`: There are no staged changes to generate a commit message for
-- `API_KEY_MISSING`: The Anthropic API key was not provided
-- `API_REQUEST_FAILED`: The request to the Anthropic API failed. Check your internet connection and API key
-- `API_NO_RESPONSE`: No response was received from the Anthropic API
-- `API_REQUEST_SETUP_ERROR`: An error occurred while setting up the API request
-- `UNKNOWN_ERROR`: An unexpected error occurred
+### API Key Related
 
-If you encounter any of these errors, the extension will display a message with more details. For persistent issues, please check your setup or contact support.
+- API key is missing or not provided
+- Invalid API key format (should start with sk-ant-api)
+- Failed to access or update secure storage
 
-## Development
+### Anthropic API Errors
 
-### Setup
+- Bad Request (400): Review your prompt and try again
+- Unauthorized (401): Invalid API key, please update and try again
+- Forbidden (403): Permission denied, review your API key
+- Rate Limited (429): Too many requests, try again later
+- Server Error (500): Anthropic API server error
 
-1. Clone the repository
-2. Install dependencies:
-```bash
-pnpm install
-```
+### Other Errors
 
-### Building
+- Failed to write commit message to Source Control
+- Failed to open commit message preview
+- No commit message was generated by the API
 
-Build the extension:
-```bash
-pnpm compile
-```
+If you encounter any of these errors, the extension will display a message with more details. For persistent issues, please check your setup or raise an issue on [GitHub](https://github.com/tsdevau/diff-commit/issues).
 
-### Running Tests
+## Local Development
 
-Run the tests using:
-```bash
-pnpm test
-```
+1. Clone the [repository](https://github.com/tsdevau/diff-commit)
+2. Install dependencies: `pnpm install`
+3. Build the extension: `pnpm compile`
+4. Run the tests: `pnpm test`
 
 ### Local Testing
 
-1. Press F5 or start the debugger in VSCode to start debugging
+1. Press F5 (<kbd>Cmd</kbd>/<kbd>Ctrl</kbd> + <kbd>Shift</kbd> + <kbd>P</kbd> and select `Debug: Start Debugging`) to start the debugger
 2. This will open a new VSCode window with the extension loaded
 3. Make changes to files and use the source control panel to test the extension