feat: evaluate built-in routing predicates and parameterized host conditions

Store transition when as JSON instead of a lookup key so designers can compose closed-set logic while hosts still supply complex refs with args. Match conditional edges before the unconditional default.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/ordo-rest.openapi.yaml

@@ -365,7 +365,7 @@ paths:
     get:
       responses:
         '200':
-          description: conditionKey catalog
+          description: host condition catalog (ref + optional params)
           content:
             application/json:
               schema:
@@ -458,6 +458,18 @@ components:
           type: string
         label:
           type: string
+        params:
+          type: array
+          items:
+            type: object
+            properties:
+              name:
+                type: string
+              type:
+                type: string
+                enum: [number, string, boolean]
+              label:
+                type: string
     ProcessDefinitionDocument:
       type: object
       required: [id, name, steps, transitions]
@@ -485,6 +497,7 @@ components:
                 type: string
                 nullable: true
               when:
-                type: string
+                type: object
+                additionalProperties: true
               priority:
                 type: integer