feat: add configurable response format for AI agents (text/JSON) (#15953)

## Summary
This PR adds configurable response format support for AI agents,
allowing them to return either plain text or structured JSON data based
on a defined schema.

## Key Features

### 1. Agent Response Format Configuration
- Added `AgentResponseFormat` type supporting:
  - `text`: Returns plain text responses (default)
  - `json`: Returns structured JSON based on defined schema
- New `AgentResponseSchema` type moved to `twenty-shared/ai` for sharing
between frontend/backend

### 2. Settings UI
- New `SettingsAgentResponseFormat` component for configuring response
format
- Visual schema builder for defining JSON output structure
- Real-time validation and preview
- Integrated into agent settings tab

### 3. Workflow Integration
- AI Agent workflow action automatically uses agent's configured
response format
- Output schema dynamically generated from agent's response format
- Workflow variable picker shows structured fields for JSON responses
- Backward compatible with existing text-only agents

### 4. Backend Implementation
- Added `convertAgentSchemaToZod` utility to validate JSON responses
- Agent executor service handles both text and JSON generation
- Automatic agent creation/cloning when adding AI agent steps to
workflows
- Unique agent naming with conflict resolution

### 5. Database Migration
- Migration `1763622159656-update-agent-response-format.ts` 
- Sets default `responseFormat` to `{"type":"text"}` for existing agents
- Updated all standard agents with proper response format

## Changes by Module

### Frontend (`twenty-front`)
- 🆕 `AgentResponseFormat` type
- 🆕 `SettingsAgentResponseFormat` component
- ✏️ Updated `WorkflowEditActionAiAgent` to support response format
configuration
- 🗑️ Removed deprecated `useAiAgentOutputSchema` hook and
`AiAgentOutputSchema` type

### Backend (`twenty-server`)
- 🆕 `AgentResponseFormat` type in agent entity
- 🆕 `convertAgentSchemaToZod` utility for schema validation
- ✏️ Updated `AiAgentExecutorService` to handle both text and JSON
generation
- ✏️ Updated `WorkflowSchemaWorkspaceService` to generate output schema
from agent config
- ✏️ Enhanced `WorkflowVersionStepOperationsWorkspaceService` with agent
creation/cloning
- 🆕 Agent naming constants for conflict resolution

### Shared (`twenty-shared`)
- 🆕 `AgentResponseSchema` type
- 🆕 `ModelConfiguration` type moved to shared package
- Updated exports in `ai/index.ts`

## Code Quality
- Removed useless comments following code style guidelines
- All linter checks passed
- Type-safe implementation with proper TypeScript types

## Testing
- ✅ Database migration tested
- ✅ Agent creation/cloning in workflows verified
- ✅ Response format switching (text ↔ JSON) validated
- ✅ Backward compatibility with existing agents confirmed

## Migration Notes
- Existing agents will have `responseFormat: {type: 'text'}` set
automatically
- No breaking changes - all existing functionality preserved
- Agents can be updated to use JSON format through settings UI

packages/twenty-front/src/modules/ai/hooks/useAiAgentOutputSchema.ts

@@ -1,66 +0,0 @@
-import { type OutputSchemaField } from '@/ai/constants/OutputFieldTypeOptions';
-import { type WorkflowAiAgentAction } from '@/workflow/types/Workflow';
-import { type AiAgentOutputSchema } from '@/workflow/workflow-variables/types/AiAgentOutputSchema';
-import { useState } from 'react';
-import { isDefined } from 'twenty-shared/utils';
-import { useDebouncedCallback } from 'use-debounce';
-import { v4 } from 'uuid';
-
-export const useAiAgentOutputSchema = (
-  outputSchema?: AiAgentOutputSchema,
-  onActionUpdate?: (action: WorkflowAiAgentAction) => void,
-  action?: WorkflowAiAgentAction,
-  readonly?: boolean,
-) => {
-  const [outputFields, setOutputFields] = useState<OutputSchemaField[]>(
-    Object.entries(outputSchema || {}).map(([name, field]) => ({
-      id: v4(),
-      name,
-      type: field.type,
-    })),
-  );
-
-  const debouncedSave = useDebouncedCallback(
-    async (fields: OutputSchemaField[]) => {
-      if (readonly === true) {
-        return;
-      }
-
-      const newOutputSchema = fields.reduce<AiAgentOutputSchema>(
-        (schema, field) => {
-          if (isDefined(field.name)) {
-            schema[field.name] = {
-              isLeaf: true,
-              type: field.type,
-              value: null,
-              label: field.name,
-            };
-          }
-          return schema;
-        },
-        {},
-      );
-
-      if (isDefined(onActionUpdate) && isDefined(action)) {
-        onActionUpdate({
-          ...action,
-          settings: {
-            ...action.settings,
-            outputSchema: newOutputSchema,
-          },
-        });
-      }
-    },
-    500,
-  );
-
-  const handleOutputSchemaChange = async (fields: OutputSchemaField[]) => {
-    setOutputFields(fields);
-    await debouncedSave(fields);
-  };
-
-  return {
-    handleOutputSchemaChange,
-    outputFields,
-  };
-};