feat: auto-install uvloop on Linux/macOS with platform gate

Move uvloop from opt-in [performance] extra to a platform-gated hard
dependency (sys_platform != 'win32'). On Linux/macOS it installs
automatically; on Windows pip/uv skips it entirely. Runtime fallback
in hanzo_async already handles ImportError gracefully.

- hanzo-async 0.1.2 → 0.1.3: uvloop now a default dep
- hanzo-mcp 0.12.7 → 0.12.8: uvloop in main deps, removed from [performance]

pkg/hanzo-async/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "hanzo-async"
-version = "0.1.2"
+version = "0.1.3"
 description = "Unified async I/O for Hanzo AI - high-performance with uvloop fallback"
 readme = "README.md"
 requires-python = ">=3.12"
@@ -18,6 +18,7 @@ classifiers = [
 keywords = ["hanzo", "async", "uvloop", "aiofiles", "high-performance"]
 dependencies = [
     "aiofiles>=23.2.1",
+    "uvloop>=0.21.0; sys_platform != 'win32'",
 ]
 
 [project.optional-dependencies]

pkg/hanzo-mcp/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "hanzo-mcp"
-version = "0.12.7"
+version = "0.12.8"
 description = "The Zen of Hanzo MCP: One server to rule them all. The ultimate MCP that orchestrates all others."
 readme = "README.md"
 requires-python = ">=3.12"
@@ -23,8 +23,9 @@ dependencies = [
     "pydantic>=2.12.5",
     "pydantic-settings>=2.12.0",
     "typing-extensions>=4.13.0",
-    # Unified async I/O (aiofiles; uvloop opt-in via performance extra)
-    "hanzo-async>=0.1.0",
+    # Unified async I/O (aiofiles + uvloop auto-installed on Linux/macOS, graceful fallback)
+    "hanzo-async>=0.1.3",
+    "uvloop>=0.22.1; sys_platform != 'win32'",
     # Hanzo tool infrastructure (all tools)
     "hanzo-tools>=0.3.0",
     "hanzo-tools-fs>=0.1.0",
@@ -116,7 +117,6 @@ test = [
 performance = [
     "ujson>=5.7.0",
     "orjson>=3.9.0",
-    "uvloop>=0.22.1; sys_platform != 'win32'",
 ]
 publish = ["twine>=4.0.2", "build>=1.0.3"]