fix: resolve MarkiTect issue handling system integration problems (issue #120)

- Fix issue manager to properly read API token and repo info from main MarkiTect config
- Update Gitea plugin to use correct repository-specific API endpoints
- Correct domain model mapping to only include valid Issue model fields
- Fix presentation layer to safely access optional body attribute
- Enable full functionality for 'markitect issues show' and 'markitect issues list' commands

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

Co-Authored-By: Claude <noreply@anthropic.com>

markitect/issues/manager.py

@@ -58,18 +58,37 @@ class IssuePluginManager:
         Returns:
             Configuration dictionary
         """
+        from config.manager import UnifiedConfigManager
+
+        # Get main markitect configuration to extract API token and settings
+        try:
+            config_manager = UnifiedConfigManager()
+            markitect_config = config_manager.get_config()
+            main_config = markitect_config.__dict__ if hasattr(markitect_config, '__dict__') else {}
+        except Exception:
+            main_config = {}
+
         if config_path is None:
             config_path = Path('.markitect/config/issues.yml')
         else:
             config_path = Path(config_path)
 
-        # Default configuration
+        # Extract configuration from main markitect config
+        gitea_url = main_config.get('gitea_url', 'http://92.205.130.254:32166')
+        api_token = main_config.get('api_token', '')
+        repo_owner = main_config.get('repo_owner', 'coulomb')
+        repo_name = main_config.get('repo_name', 'markitect_project')
+
+        # Default configuration using main config values
         default_config = {
             'default_backend': 'gitea',
             'backends': {
                 'gitea': {
-                    'url': 'http://92.205.130.254:32166',
-                    'repo': 'coulomb/markitect_project'
+                    'url': gitea_url,
+                    'token': api_token,
+                    'repo_owner': repo_owner,
+                    'repo_name': repo_name,
+                    'repo': f'{repo_owner}/{repo_name}'
                 },
                 'local': {
                     'directory': '.markitect/issues',
@@ -88,6 +107,17 @@ class IssuePluginManager:
             # Merge with defaults
             merged_config = default_config.copy()
             merged_config.update(config)
+
+            # Ensure gitea backend has token from main config if not overridden
+            if 'backends' in merged_config and 'gitea' in merged_config['backends']:
+                gitea_config = merged_config['backends']['gitea']
+                if not gitea_config.get('token'):
+                    gitea_config['token'] = api_token
+                if not gitea_config.get('repo_owner'):
+                    gitea_config['repo_owner'] = repo_owner
+                if not gitea_config.get('repo_name'):
+                    gitea_config['repo_name'] = repo_name
+
             return merged_config
         except Exception:
             # Return defaults if config loading fails