feat(config): Restructure .taskmasterconfig and enhance gateway integration

Config Structure Changes and Gateway Integration

## Configuration Structure Changes
- Restructured .taskmasterconfig to use 'account' section for user settings
- Moved userId, userEmail, mode, telemetryEnabled from global to account section
- API keys remain isolated in .env file (not accessible to AI)
- Enhanced getUserId() to always return value, never null (sets default '1234567890')

## Gateway Integration Enhancements
- Updated registerUserWithGateway() to accept both email and userId parameters
- Enhanced /auth/init endpoint integration for existing user validation
- API key updates automatically written to .env during registration process
- Improved user identification and validation flow

## Code Updates for New Structure
- Fixed config-manager.js getter functions for account section access
- Updated user-management.js to use config.account.userId/mode
- Modified telemetry-submission.js to read from account section
- Added getTelemetryEnabled() function with proper account section access
- Enhanced telemetry configuration reading with new structure

## Comprehensive Test Updates
- Updated integration tests (init-config.test.js) for new config structure
- Fixed unit tests (config-manager.test.js) with updated default config
- Updated telemetry tests (telemetry-submission.test.js) for account structure
- Added missing getTelemetryEnabled mock to ai-services-unified.test.js
- Fixed all test expectations to use config.account.* instead of config.global.*
- Removed references to deprecated config.subscription object

## Configuration Access Consistency
- Standardized configuration access patterns across entire codebase
- Clean separation: user settings in account, API keys in .env, models/global in respective sections
- All tests passing with new configuration structure
- Maintained backward compatibility during transition

Changes support enhanced telemetry system with proper user management and gateway integration while maintaining security through API key isolation.

scripts/modules/user-management.js

@@ -77,14 +77,14 @@ function updateUserConfig(userId, token, mode, explicitRoot = null) {
   try {
     const config = getConfig(explicitRoot);
 
-    // Ensure global section exists
-    if (!config.global) {
-      config.global = {};
+    // Ensure account section exists
+    if (!config.account) {
+      config.account = {};
     }
 
-    // Update user configuration
-    config.global.userId = userId;
-    config.global.mode = mode; // 'byok' or 'hosted'
+    // Update user configuration in account section
+    config.account.userId = userId;
+    config.account.mode = mode; // 'byok' or 'hosted'
 
     // Write API token to .env file (not config)
     if (token) {
@@ -169,7 +169,7 @@ function writeApiKeyToEnv(token, explicitRoot = null) {
 function getUserMode(explicitRoot = null) {
   try {
     const config = getConfig(explicitRoot);
-    return config?.global?.mode || "unknown";
+    return config?.account?.mode || "unknown";
   } catch (error) {
     log("error", `Error getting user mode: ${error.message}`);
     return "unknown";