Add types.sx gradual type system spec module with 44 tests

Implements subtype checking, type inference, type narrowing, and
component call-site checking. All type logic is in types.sx (spec),
bootstrapped to every host. Adds test-types.sx with full coverage.

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

shared/sx/ref/platform_py.py

@@ -307,6 +307,14 @@ def component_affinity(c):
     return getattr(c, 'affinity', 'auto')
 
 
+def component_param_types(c):
+    return getattr(c, 'param_types', None)
+
+
+def component_set_param_types(c, d):
+    c.param_types = d
+
+
 def macro_params(m):
     return m.params
 
@@ -1428,6 +1436,7 @@ SPEC_MODULES = {
     "router": ("router.sx", "router (client-side route matching)"),
     "engine": ("engine.sx", "engine (fetch/swap/trigger pure logic)"),
     "signals": ("signals.sx", "signals (reactive signal runtime)"),
+    "types": ("types.sx", "types (gradual type system)"),
 }
 
 EXTENSION_NAMES = {"continuations"}