fix(ci): fix black/ruff failures, add CoC and PR template

- Fix Python formatting (sync no longer strips blank lines from .py files)
- Remove test_community_build.py (tests private sync module)
- Fix ruff warnings in test files
- Add CODE_OF_CONDUCT.md
- Add .github/PULL_REQUEST_TEMPLATE.md

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/tool_registry.py

@@ -13,6 +13,7 @@ from pydantic import BaseModel, ConfigDict, Field
 
 logger = logging.getLogger(__name__)
 
+
 class ToolDefinition(BaseModel):
     """
     Type-safe tool definition.
@@ -42,6 +43,7 @@ class ToolDefinition(BaseModel):
 
     model_config = ConfigDict(arbitrary_types_allowed=True)  # Allow Callable type
 
+
 class ToolRegistry:
     """
     Central registry for all MCP tools.
@@ -208,9 +210,11 @@ class ToolRegistry:
         counts_str = ", ".join(f"{k}: {v}" for k, v in counts.items())
         return f"ToolRegistry(total={self.get_count()}, {counts_str})"
 
+
 # Singleton instance
 _tool_registry: ToolRegistry | None = None
 
+
 def get_tool_registry() -> ToolRegistry:
     """
     Get the singleton tool registry instance.