refactor(workflow): convert all plugins to class/struct + factory pattern

- Python: class extending NodeExecutor + factory.py (80+ plugins)
- TypeScript: class implements NodeExecutor + factory.ts (7 groups, 116 classes)
- Go: struct with methods + factory.go (36 plugins)
- Rust: struct impl NodeExecutor trait + factory.rs (54 plugins)
- Mojo: struct + factory.mojo (11 plugins)

All package.json files now include:
- files array listing source files
- metadata.class/struct field
- metadata.entrypoint field

This enables a unified plugin loading system across all languages
with no import side effects (Spring-style DI pattern).

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

workflow/plugins/python/string/string_concat/factory.py

@@ -0,0 +1,7 @@
+"""Factory for StringConcat plugin."""
+
+from .string_concat import StringConcat
+
+
+def create():
+    return StringConcat()

workflow/plugins/python/string/string_concat/package.json

@@ -1,13 +1,16 @@
 {
   "name": "@metabuilder/string_concat",
   "version": "1.0.0",
-  "description": "string_concat plugin",
+  "description": "Concatenate multiple strings",
   "author": "MetaBuilder",
   "license": "MIT",
   "keywords": ["string", "workflow", "plugin"],
   "main": "string_concat.py",
+  "files": ["string_concat.py", "factory.py"],
   "metadata": {
     "plugin_type": "string.concat",
-    "category": "string"
+    "category": "string",
+    "class": "StringConcat",
+    "entrypoint": "execute"
   }
 }

workflow/plugins/python/string/string_concat/string_concat.py

@@ -1,10 +1,16 @@
 """Workflow plugin: concatenate strings."""
 
+from ...base import NodeExecutor
 
-def run(_runtime, inputs):
+
+class StringConcat(NodeExecutor):
     """Concatenate multiple strings."""
-    strings = inputs.get("strings", [])
-    separator = inputs.get("separator", "")
 
-    str_list = [str(s) for s in strings]
-    return {"result": separator.join(str_list)}
+    node_type = "string.concat"
+    category = "string"
+    description = "Concatenate multiple strings"
+
+    def execute(self, inputs, runtime=None):
+        separator = inputs.get("separator", "")
+        strings = inputs.get("strings", inputs.get("values", []))
+        return {"result": separator.join(str(s) for s in strings)}

workflow/plugins/python/string/string_format/factory.py

@@ -0,0 +1,7 @@
+"""Factory for StringFormat plugin."""
+
+from .string_format import StringFormat
+
+
+def create():
+    return StringFormat()

workflow/plugins/python/string/string_format/package.json

@@ -1,13 +1,16 @@
 {
   "name": "@metabuilder/string_format",
   "version": "1.0.0",
-  "description": "string_format plugin",
+  "description": "Format string with variables",
   "author": "MetaBuilder",
   "license": "MIT",
   "keywords": ["string", "workflow", "plugin"],
   "main": "string_format.py",
+  "files": ["string_format.py", "factory.py"],
   "metadata": {
     "plugin_type": "string.format",
-    "category": "string"
+    "category": "string",
+    "class": "StringFormat",
+    "entrypoint": "execute"
   }
 }

workflow/plugins/python/string/string_format/string_format.py

@@ -1,13 +1,19 @@
 """Workflow plugin: format string with variables."""
 
+from ...base import NodeExecutor
 
-def run(_runtime, inputs):
+
+class StringFormat(NodeExecutor):
     """Format string with variables."""
-    template = inputs.get("template", "")
-    variables = inputs.get("variables", {})
 
-    try:
-        result = template.format(**variables)
-        return {"result": result}
-    except (KeyError, ValueError) as e:
-        return {"result": template, "error": str(e)}
+    node_type = "string.format"
+    category = "string"
+    description = "Format string with variables"
+
+    def execute(self, inputs, runtime=None):
+        template = inputs.get("template", "")
+        variables = inputs.get("variables", {})
+        try:
+            return {"result": template.format(**variables)}
+        except (KeyError, ValueError) as e:
+            return {"result": template, "error": str(e)}

workflow/plugins/python/string/string_length/factory.py

@@ -0,0 +1,7 @@
+"""Factory for StringLength plugin."""
+
+from .string_length import StringLength
+
+
+def create():
+    return StringLength()

workflow/plugins/python/string/string_length/package.json

@@ -1,13 +1,16 @@
 {
   "name": "@metabuilder/string_length",
   "version": "1.0.0",
-  "description": "string_length plugin",
+  "description": "Get string length",
   "author": "MetaBuilder",
   "license": "MIT",
   "keywords": ["string", "workflow", "plugin"],
   "main": "string_length.py",
+  "files": ["string_length.py", "factory.py"],
   "metadata": {
     "plugin_type": "string.length",
-    "category": "string"
+    "category": "string",
+    "class": "StringLength",
+    "entrypoint": "execute"
   }
 }

workflow/plugins/python/string/string_length/string_length.py

@@ -1,7 +1,15 @@
 """Workflow plugin: get string length."""
 
+from ...base import NodeExecutor
 
-def run(_runtime, inputs):
-    """Get length of a string."""
-    text = inputs.get("text", "")
-    return {"result": len(text)}
+
+class StringLength(NodeExecutor):
+    """Get string length."""
+
+    node_type = "string.length"
+    category = "string"
+    description = "Get string length"
+
+    def execute(self, inputs, runtime=None):
+        value = str(inputs.get("value", inputs.get("text", "")))
+        return {"result": len(value)}

workflow/plugins/python/string/string_lower/factory.py

@@ -0,0 +1,7 @@
+"""Factory for StringLower plugin."""
+
+from .string_lower import StringLower
+
+
+def create():
+    return StringLower()

workflow/plugins/python/string/string_lower/package.json

@@ -1,13 +1,16 @@
 {
   "name": "@metabuilder/string_lower",
   "version": "1.0.0",
-  "description": "string_lower plugin",
+  "description": "Convert string to lowercase",
   "author": "MetaBuilder",
   "license": "MIT",
   "keywords": ["string", "workflow", "plugin"],
   "main": "string_lower.py",
+  "files": ["string_lower.py", "factory.py"],
   "metadata": {
     "plugin_type": "string.lower",
-    "category": "string"
+    "category": "string",
+    "class": "StringLower",
+    "entrypoint": "execute"
   }
 }

workflow/plugins/python/string/string_lower/string_lower.py

@@ -1,7 +1,15 @@
 """Workflow plugin: convert string to lowercase."""
 
+from ...base import NodeExecutor
 
-def run(_runtime, inputs):
+
+class StringLower(NodeExecutor):
     """Convert string to lowercase."""
-    text = inputs.get("text", "")
-    return {"result": text.lower()}
+
+    node_type = "string.lower"
+    category = "string"
+    description = "Convert string to lowercase"
+
+    def execute(self, inputs, runtime=None):
+        value = str(inputs.get("value", inputs.get("text", "")))
+        return {"result": value.lower()}

workflow/plugins/python/string/string_replace/factory.py

@@ -0,0 +1,7 @@
+"""Factory for StringReplace plugin."""
+
+from .string_replace import StringReplace
+
+
+def create():
+    return StringReplace()

workflow/plugins/python/string/string_replace/package.json

@@ -1,13 +1,16 @@
 {
   "name": "@metabuilder/string_replace",
   "version": "1.0.0",
-  "description": "string_replace plugin",
+  "description": "Replace occurrences in string",
   "author": "MetaBuilder",
   "license": "MIT",
   "keywords": ["string", "workflow", "plugin"],
   "main": "string_replace.py",
+  "files": ["string_replace.py", "factory.py"],
   "metadata": {
     "plugin_type": "string.replace",
-    "category": "string"
+    "category": "string",
+    "class": "StringReplace",
+    "entrypoint": "execute"
   }
 }

workflow/plugins/python/string/string_replace/string_replace.py

@@ -1,12 +1,18 @@
 """Workflow plugin: replace in string."""
 
+from ...base import NodeExecutor
 
-def run(_runtime, inputs):
+
+class StringReplace(NodeExecutor):
     """Replace occurrences in string."""
-    text = inputs.get("text", "")
-    old = inputs.get("old", "")
-    new = inputs.get("new", "")
-    count = inputs.get("count", -1)
 
-    result = text.replace(old, new, count)
-    return {"result": result}
+    node_type = "string.replace"
+    category = "string"
+    description = "Replace occurrences in string"
+
+    def execute(self, inputs, runtime=None):
+        value = str(inputs.get("value", inputs.get("text", "")))
+        old = inputs.get("old", inputs.get("search", ""))
+        new = inputs.get("new", inputs.get("replacement", ""))
+        count = inputs.get("count", -1)
+        return {"result": value.replace(old, new, count)}

workflow/plugins/python/string/string_split/factory.py

@@ -0,0 +1,7 @@
+"""Factory for StringSplit plugin."""
+
+from .string_split import StringSplit
+
+
+def create():
+    return StringSplit()

workflow/plugins/python/string/string_split/package.json

@@ -1,13 +1,16 @@
 {
   "name": "@metabuilder/string_split",
   "version": "1.0.0",
-  "description": "string_split plugin",
+  "description": "Split string by separator",
   "author": "MetaBuilder",
   "license": "MIT",
   "keywords": ["string", "workflow", "plugin"],
   "main": "string_split.py",
+  "files": ["string_split.py", "factory.py"],
   "metadata": {
     "plugin_type": "string.split",
-    "category": "string"
+    "category": "string",
+    "class": "StringSplit",
+    "entrypoint": "execute"
   }
 }

workflow/plugins/python/string/string_split/string_split.py

@@ -1,15 +1,19 @@
 """Workflow plugin: split string."""
 
+from ...base import NodeExecutor
 
-def run(_runtime, inputs):
+
+class StringSplit(NodeExecutor):
     """Split string by separator."""
-    text = inputs.get("text", "")
-    separator = inputs.get("separator", " ")
-    max_splits = inputs.get("max_splits")
 
-    if max_splits is not None:
-        result = text.split(separator, max_splits)
-    else:
-        result = text.split(separator)
+    node_type = "string.split"
+    category = "string"
+    description = "Split string by separator"
 
-    return {"result": result}
+    def execute(self, inputs, runtime=None):
+        text = str(inputs.get("text", inputs.get("value", "")))
+        separator = inputs.get("separator", " ")
+        max_splits = inputs.get("max_splits", inputs.get("limit"))
+        if max_splits is not None:
+            return {"result": text.split(separator, max_splits)}
+        return {"result": text.split(separator)}

workflow/plugins/python/string/string_trim/factory.py

@@ -0,0 +1,7 @@
+"""Factory for StringTrim plugin."""
+
+from .string_trim import StringTrim
+
+
+def create():
+    return StringTrim()

workflow/plugins/python/string/string_trim/package.json

@@ -1,13 +1,16 @@
 {
   "name": "@metabuilder/string_trim",
   "version": "1.0.0",
-  "description": "string_trim plugin",
+  "description": "Trim whitespace from string",
   "author": "MetaBuilder",
   "license": "MIT",
   "keywords": ["string", "workflow", "plugin"],
   "main": "string_trim.py",
+  "files": ["string_trim.py", "factory.py"],
   "metadata": {
     "plugin_type": "string.trim",
-    "category": "string"
+    "category": "string",
+    "class": "StringTrim",
+    "entrypoint": "execute"
   }
 }

workflow/plugins/python/string/string_trim/string_trim.py

@@ -1,16 +1,20 @@
 """Workflow plugin: trim whitespace from string."""
 
+from ...base import NodeExecutor
 
-def run(_runtime, inputs):
+
+class StringTrim(NodeExecutor):
     """Trim whitespace from string."""
-    text = inputs.get("text", "")
-    mode = inputs.get("mode", "both")
 
-    if mode == "start":
-        result = text.lstrip()
-    elif mode == "end":
-        result = text.rstrip()
-    else:
-        result = text.strip()
+    node_type = "string.trim"
+    category = "string"
+    description = "Trim whitespace from string"
 
-    return {"result": result}
+    def execute(self, inputs, runtime=None):
+        value = str(inputs.get("value", inputs.get("text", "")))
+        mode = inputs.get("mode", "both")
+        if mode == "start":
+            return {"result": value.lstrip()}
+        elif mode == "end":
+            return {"result": value.rstrip()}
+        return {"result": value.strip()}

workflow/plugins/python/string/string_upper/factory.py

@@ -0,0 +1,7 @@
+"""Factory for StringUpper plugin."""
+
+from .string_upper import StringUpper
+
+
+def create():
+    return StringUpper()

workflow/plugins/python/string/string_upper/package.json

@@ -1,13 +1,16 @@
 {
   "name": "@metabuilder/string_upper",
   "version": "1.0.0",
-  "description": "string_upper plugin",
+  "description": "Convert string to uppercase",
   "author": "MetaBuilder",
   "license": "MIT",
   "keywords": ["string", "workflow", "plugin"],
   "main": "string_upper.py",
+  "files": ["string_upper.py", "factory.py"],
   "metadata": {
     "plugin_type": "string.upper",
-    "category": "string"
+    "category": "string",
+    "class": "StringUpper",
+    "entrypoint": "execute"
   }
 }

workflow/plugins/python/string/string_upper/string_upper.py

@@ -1,7 +1,15 @@
 """Workflow plugin: convert string to uppercase."""
 
+from ...base import NodeExecutor
 
-def run(_runtime, inputs):
+
+class StringUpper(NodeExecutor):
     """Convert string to uppercase."""
-    text = inputs.get("text", "")
-    return {"result": text.upper()}
+
+    node_type = "string.upper"
+    category = "string"
+    description = "Convert string to uppercase"
+
+    def execute(self, inputs, runtime=None):
+        value = str(inputs.get("value", inputs.get("text", "")))
+        return {"result": value.upper()}