DynamicSlot: typed option dispatch driven by TypeResolver

Replaces the old connected/unconnected fixed-child DynamicSlot with a
type-keyed option list. Each Option declares a 'when' condition (None,
io.AnyType, a single ComfyType, a list, or a MultiType.Input) and the
child inputs revealed when that condition matches the slot's resolved
upstream type.

Selection happens at schema-finalization time using live_input_types
computed by TypeResolver, so API-only workflows (no frontend) get the
same expansion the UI would.

- _io.py: redesign DynamicSlot.Input / Option; auto-derive slotType as
  the union of all non-None when sets; expose it via as_dict so the
  frontend knows what types are accepted; the class io_type stays
  COMFY_DYNAMICSLOT_V3 as the parse-time dispatch tag.
- type_resolver.py: return the auto-derived _slot_io_type for
  DynamicSlot.Input; document the AnyType (*) limitation.
- execution.py: validate links into a DynamicSlot against slotType,
  not the dispatch tag COMFY_DYNAMICSLOT_V3.
- tests: new test_dynamic_slot.py + regression coverage in
  test_type_resolver.py.

Amp-Thread-ID: https://ampcode.com/threads/T-019e8568-f382-743d-a97f-0de3ff29d501
Co-authored-by: Amp <amp@ampcode.com>

comfy_execution/type_resolver.py

@@ -7,6 +7,13 @@ or unresolvable wildcards.
 
 Works against either a raw prompt dict or a ``DynamicPrompt``. All resolved
 values are strings, so resolver state is cross-process serializable.
+
+Known limitation: when an upstream node declares its output as ``AnyType``
+(``"*"``) — Reroute, generic If/Else, many V1 utility nodes — the resolver
+returns ``"*"``. It has no way to introspect the runtime value to recover a
+more specific type. Downstream consumers (e.g. :py:class:`DynamicSlot`) will
+treat such links as AnyType and select their ``AnyType`` branch (or none),
+not a concrete-type branch.
 """
 
 from __future__ import annotations
@@ -328,10 +335,8 @@ class TypeResolver:
             except Exception:
                 return ANY_TYPE
         if isinstance(inp, io.DynamicSlot.Input):
-            try:
-                return inp.slot.get_io_type()
-            except Exception:
-                return ANY_TYPE
+            # Auto-derived slot type — comma-joined union of all option `when` types.
+            return getattr(inp, "_slot_io_type", ANY_TYPE)
         # DynamicCombo's "type" is a key selector, not a connection type.
         if isinstance(inp, io.DynamicCombo.Input):
             return ANY_TYPE