feat: make @anthropic-ai/claude-code an optional dependency

This change makes the Claude Code SDK package optional, preventing installation failures for users who don't need Claude Code functionality.

Changes:
- Added @anthropic-ai/claude-code to optionalDependencies in package.json
- Implemented lazy loading in language-model.js to only import the SDK when actually used
- Updated documentation to explain the optional installation requirement
- Applied formatting fixes to ensure code consistency

Benefits:
- Users without Claude Code subscriptions don't need to install the dependency
- Reduces package size for users who don't use Claude Code
- Prevents installation failures if the package is unavailable
- Provides clear error messages when the package is needed but not installed

The implementation uses dynamic imports to load the SDK only when doGenerate() or doStream() is called, ensuring the provider can be instantiated without the package present.

scripts/modules/update-config-tokens.js

@@ -20,29 +20,33 @@ export function updateConfigMaxTokens(configPath) {
 	try {
 		// Load supported models
 		const supportedModelsPath = path.join(__dirname, 'supported-models.json');
-		const supportedModels = JSON.parse(fs.readFileSync(supportedModelsPath, 'utf-8'));
-		
+		const supportedModels = JSON.parse(
+			fs.readFileSync(supportedModelsPath, 'utf-8')
+		);
+
 		// Load config
 		const config = JSON.parse(fs.readFileSync(configPath, 'utf-8'));
-		
+
 		// Update each role's maxTokens if the model exists in supported-models.json
 		const roles = ['main', 'research', 'fallback'];
-		
+
 		for (const role of roles) {
 			if (config.models && config.models[role]) {
 				const provider = config.models[role].provider;
 				const modelId = config.models[role].modelId;
-				
+
 				// Find the model in supported models
 				if (supportedModels[provider]) {
-					const modelData = supportedModels[provider].find(m => m.id === modelId);
+					const modelData = supportedModels[provider].find(
+						(m) => m.id === modelId
+					);
 					if (modelData && modelData.max_tokens) {
 						config.models[role].maxTokens = modelData.max_tokens;
 					}
 				}
 			}
 		}
-		
+
 		// Write back the updated config
 		fs.writeFileSync(configPath, JSON.stringify(config, null, 2));
 		return true;
@@ -50,4 +54,4 @@ export function updateConfigMaxTokens(configPath) {
 		console.error('Error updating config maxTokens:', error.message);
 		return false;
 	}
-}
+}