feat: Add Python plugins from AutoMetabuilder + restructure workflow folder

Restructure workflow/ for multi-language plugin support:
- Rename src/ to core/ (engine code: DAG executor, registry, types)
- Create executor/{cpp,python,ts}/ for language-specific runtimes
- Consolidate plugins to plugins/{ts,python}/ by language then category

Add 80+ Python plugins from AutoMetabuilder in 14 categories:
- control: bot control, switch logic, state management
- convert: type conversions (json, boolean, dict, list, number, string)
- core: AI requests, context management, tool calls
- dict: dictionary operations (get, set, keys, values, merge)
- list: list operations (concat, find, sort, slice, filter)
- logic: boolean logic (and, or, xor, equals, comparisons)
- math: arithmetic operations (add, subtract, multiply, power, etc.)
- string: string manipulation (concat, split, replace, format)
- notifications: Slack, Discord integrations
- test: assertion helpers and test suite runner
- tools: file operations, git, docker, testing utilities
- utils: filtering, mapping, reducing, condition branching
- var: variable store operations (get, set, delete, exists)
- web: Flask server, environment variables, JSON handling

Add language executor runtimes:
- TypeScript: direct import execution (default, fast startup)
- Python: child process with JSON stdin/stdout communication
- C++: placeholder for native FFI bindings (Phase 3)

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

workflow/plugins/python/logic/__init__.py

@@ -0,0 +1 @@
+"""Boolean logic plugins."""

workflow/plugins/python/logic/logic_and.py

@@ -0,0 +1,7 @@
+"""Workflow plugin: logical AND."""
+
+
+def run(_runtime, inputs):
+    """Perform logical AND on values."""
+    values = inputs.get("values", [])
+    return {"result": all(values)}

workflow/plugins/python/logic/logic_equals.py

@@ -0,0 +1,8 @@
+"""Workflow plugin: equality comparison."""
+
+
+def run(_runtime, inputs):
+    """Check if two values are equal."""
+    a = inputs.get("a")
+    b = inputs.get("b")
+    return {"result": a == b}

workflow/plugins/python/logic/logic_gt.py

@@ -0,0 +1,8 @@
+"""Workflow plugin: greater than comparison."""
+
+
+def run(_runtime, inputs):
+    """Check if a > b."""
+    a = inputs.get("a")
+    b = inputs.get("b")
+    return {"result": a > b}

workflow/plugins/python/logic/logic_gte.py

@@ -0,0 +1,8 @@
+"""Workflow plugin: greater than or equal comparison."""
+
+
+def run(_runtime, inputs):
+    """Check if a >= b."""
+    a = inputs.get("a")
+    b = inputs.get("b")
+    return {"result": a >= b}

workflow/plugins/python/logic/logic_in.py

@@ -0,0 +1,8 @@
+"""Workflow plugin: membership test."""
+
+
+def run(_runtime, inputs):
+    """Check if value is in collection."""
+    value = inputs.get("value")
+    collection = inputs.get("collection", [])
+    return {"result": value in collection}

workflow/plugins/python/logic/logic_lt.py

@@ -0,0 +1,8 @@
+"""Workflow plugin: less than comparison."""
+
+
+def run(_runtime, inputs):
+    """Check if a < b."""
+    a = inputs.get("a")
+    b = inputs.get("b")
+    return {"result": a < b}

workflow/plugins/python/logic/logic_lte.py

@@ -0,0 +1,8 @@
+"""Workflow plugin: less than or equal comparison."""
+
+
+def run(_runtime, inputs):
+    """Check if a <= b."""
+    a = inputs.get("a")
+    b = inputs.get("b")
+    return {"result": a <= b}

workflow/plugins/python/logic/logic_or.py

@@ -0,0 +1,7 @@
+"""Workflow plugin: logical OR."""
+
+
+def run(_runtime, inputs):
+    """Perform logical OR on values."""
+    values = inputs.get("values", [])
+    return {"result": any(values)}

workflow/plugins/python/logic/logic_xor.py

@@ -0,0 +1,8 @@
+"""Workflow plugin: logical XOR."""
+
+
+def run(_runtime, inputs):
+    """Perform logical XOR on two values."""
+    a = inputs.get("a", False)
+    b = inputs.get("b", False)
+    return {"result": bool(a) != bool(b)}