feat: add Claude Code provider support

Implements Claude Code as a new AI provider that uses the Claude Code CLI
without requiring API keys. This enables users to leverage Claude models
through their local Claude Code installation.

Key changes:
- Add complete AI SDK v1 implementation for Claude Code provider
  - Custom SDK with streaming/non-streaming support
  - Session management for conversation continuity
  - JSON extraction for object generation mode
  - Support for advanced settings (maxTurns, allowedTools, etc.)

- Integrate Claude Code into Task Master's provider system
  - Update ai-services-unified.js to handle keyless authentication
  - Add provider to supported-models.json with opus/sonnet models
  - Ensure correct maxTokens values are applied (opus: 32000, sonnet: 64000)

- Fix maxTokens configuration issue
  - Add max_tokens property to getAvailableModels() output
  - Update setModel() to properly handle claude-code models
  - Create update-config-tokens.js utility for init process

- Add comprehensive documentation
  - User guide with configuration examples
  - Advanced settings explanation and future integration options

The implementation maintains full backward compatibility with existing
providers while adding seamless Claude Code support to all Task Master
commands.

scripts/init.js

@@ -28,6 +28,7 @@ import {
 	convertAllRulesToProfileRules,
 	getRulesProfile
 } from '../src/utils/rule-transformer.js';
+import { updateConfigMaxTokens } from './modules/update-config-tokens.js';
 
 import { execSync } from 'child_process';
 import {
@@ -506,6 +507,14 @@ function createProjectStructure(
 			...replacements
 		}
 	);
+	
+	// Update config.json with correct maxTokens values from supported-models.json
+	const configPath = path.join(targetDir, TASKMASTER_CONFIG_FILE);
+	if (updateConfigMaxTokens(configPath)) {
+		log('info', 'Updated config with correct maxTokens values');
+	} else {
+		log('warn', 'Could not update maxTokens in config');
+	}
 
 	// Copy .gitignore
 	copyTemplateFile('gitignore', path.join(targetDir, GITIGNORE_FILE));