feat: Propagate workflow plugins to Go, Rust, C++, and Mojo

Multi-language workflow plugin system following Python's structure:
- Each plugin in its own directory with implementation + package.json
- Category-level package.json manifests listing all plugins
- Consistent interface: run(runtime, inputs) -> outputs

Languages added:
- Go: math, string, logic, list, dict, var, convert (25+ plugins)
- Rust: math, string, logic, list, convert, var (50+ functions)
- C++: header-only math, string, logic, var, convert (30+ plugins)
- Mojo: math, string, list with systems programming features

Python structure fixed:
- Reorganized flat files into plugin subdirectories
- Added package.json metadata to all 120+ plugins
- Added missing backend category (15 plugins)
- Category manifests with plugin lists

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

workflow/plugins/python/utils/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "@metabuilder/workflow-plugins-utils",
+  "version": "1.0.0",
+  "description": "Utility function plugins",
+  "author": "MetaBuilder",
+  "license": "MIT",
+  "keywords": ["utils", "utility", "workflow", "plugins"],
+  "metadata": {
+    "category": "utils",
+    "plugin_count": 7
+  },
+  "plugins": [
+    "utils_check_mvp",
+    "utils_filter_list",
+    "utils_format_date",
+    "utils_generate_uuid",
+    "utils_hash",
+    "utils_map_list",
+    "utils_sleep"
+  ]
+}

workflow/plugins/python/utils/utils_branch_condition/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "@metabuilder/utils_branch_condition",
+  "version": "1.0.0",
+  "description": "utils_branch_condition plugin",
+  "author": "MetaBuilder",
+  "license": "MIT",
+  "keywords": ["utils", "workflow", "plugin"],
+  "main": "utils_branch_condition.py",
+  "metadata": {
+    "plugin_type": "utils.branch_condition",
+    "category": "utils"
+  }
+}

workflow/plugins/python/utils/utils_check_mvp/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "@metabuilder/utils_check_mvp",
+  "version": "1.0.0",
+  "description": "utils_check_mvp plugin",
+  "author": "MetaBuilder",
+  "license": "MIT",
+  "keywords": ["utils", "workflow", "plugin"],
+  "main": "utils_check_mvp.py",
+  "metadata": {
+    "plugin_type": "utils.check_mvp",
+    "category": "utils"
+  }
+}

workflow/plugins/python/utils/utils_filter_list/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "@metabuilder/utils_filter_list",
+  "version": "1.0.0",
+  "description": "utils_filter_list plugin",
+  "author": "MetaBuilder",
+  "license": "MIT",
+  "keywords": ["utils", "workflow", "plugin"],
+  "main": "utils_filter_list.py",
+  "metadata": {
+    "plugin_type": "utils.filter_list",
+    "category": "utils"
+  }
+}

workflow/plugins/python/utils/utils_map_list/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "@metabuilder/utils_map_list",
+  "version": "1.0.0",
+  "description": "utils_map_list plugin",
+  "author": "MetaBuilder",
+  "license": "MIT",
+  "keywords": ["utils", "workflow", "plugin"],
+  "main": "utils_map_list.py",
+  "metadata": {
+    "plugin_type": "utils.map_list",
+    "category": "utils"
+  }
+}

workflow/plugins/python/utils/utils_not/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "@metabuilder/utils_not",
+  "version": "1.0.0",
+  "description": "utils_not plugin",
+  "author": "MetaBuilder",
+  "license": "MIT",
+  "keywords": ["utils", "workflow", "plugin"],
+  "main": "utils_not.py",
+  "metadata": {
+    "plugin_type": "utils.not",
+    "category": "utils"
+  }
+}

workflow/plugins/python/utils/utils_reduce_list/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "@metabuilder/utils_reduce_list",
+  "version": "1.0.0",
+  "description": "utils_reduce_list plugin",
+  "author": "MetaBuilder",
+  "license": "MIT",
+  "keywords": ["utils", "workflow", "plugin"],
+  "main": "utils_reduce_list.py",
+  "metadata": {
+    "plugin_type": "utils.reduce_list",
+    "category": "utils"
+  }
+}

workflow/plugins/python/utils/utils_update_roadmap/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "@metabuilder/utils_update_roadmap",
+  "version": "1.0.0",
+  "description": "utils_update_roadmap plugin",
+  "author": "MetaBuilder",
+  "license": "MIT",
+  "keywords": ["utils", "workflow", "plugin"],
+  "main": "utils_update_roadmap.py",
+  "metadata": {
+    "plugin_type": "utils.update_roadmap",
+    "category": "utils"
+  }
+}