refactor: Update example generation and schema handling

- Remove unused `generate_example_call` and `generate_example_response` functions
- Rename `example_call` to `example_request` in `DocMethod`
- Update schema example extraction to use `schema.example` directly
- Introduce `generate_request_example` and `generate_response_example` for dynamic example generation
- Change type of `id` from string to number in schema examples

PS: The work is still in progress

examples/hero/heroserver/openrpc.json

@@ -37,8 +37,8 @@
           "description": "The unique identifier of the comment to retrieve.",
           "required": true,
           "schema": {
-            "type": "string",
-            "example": "comment_12345"
+            "type": "number",
+            "example": "1"
           }
         },
         {
@@ -57,7 +57,7 @@
         "schema": {
           "type": "object",
           "example": {
-            "id": "comment_12345",
+            "id": 1,
             "text": "This is a sample comment",
             "created_at": "2024-01-15T10:30:00Z"
           }