fix(workflow): restore initial input fields on code step creation (#20756)

## Summary

- Fixes a regression from #20208 where creating a new CODE workflow step
shows no input fields
- The split-triggers PR removed `SEED_LOGIC_FUNCTION_INPUT_SCHEMA` and
replaced `toolInputSchema` with `workflowActionTriggerSettings`, but
`CodeStepBuildService.createCodeStepLogicFunction` was not updated to
pass the seed schema — causing `logicFunctionInput` to default to `{}`
and no fields to render
- Adds `SEED_WORKFLOW_ACTION_TRIGGER_SETTINGS` constant (matching the
seed template's `{ a: string, b: number }` params) and passes it when
creating the seed logic function

## Test plan

- [x] Unit test updated to assert `logicFunctionInput` contains `{ a:
null, b: null }` on code step creation
- [x] Create a new CODE step in the workflow builder and verify input
fields `a` and `b` appear immediately

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

packages/twenty-shared/src/logic-function/constants/SeedWorkflowActionTriggerSettings.ts

@@ -0,0 +1,13 @@
+import { type WorkflowActionTriggerSettings } from '@/application';
+import { jsonSchemaToInputSchema } from '@/logic-function/json-schema-to-input-schema';
+
+export const SEED_WORKFLOW_ACTION_TRIGGER_SETTINGS: WorkflowActionTriggerSettings =
+  {
+    inputSchema: jsonSchemaToInputSchema({
+      type: 'object',
+      properties: {
+        a: { type: 'string' },
+        b: { type: 'number' },
+      },
+    }),
+  };

packages/twenty-shared/src/logic-function/index.ts

@@ -8,6 +8,7 @@
  */
 
 export { DEFAULT_TOOL_INPUT_SCHEMA } from './constants/DefaultToolInputSchema';
+export { SEED_WORKFLOW_ACTION_TRIGGER_SETTINGS } from './constants/SeedWorkflowActionTriggerSettings';
 export { getInputSchemaFromSourceCode } from './get-input-schema-from-source-code';
 export { getOutputSchemaFromValue } from './get-output-schema-from-value';
 export type { InputJsonSchema } from './input-json-schema.type';