feat: improve AI chat - system prompt, tool output, context window display (#17769)

⚠️ **AI-generated PR — not ready for review** ⚠️

cc @FelixMalfait

---

## Changes

### System prompt improvements
- Explicit skill-before-tools workflow to prevent the model from calling
tools without loading the matching skill first
- Data efficiency guidance (default small limits, use filters)
- Pluralized `load_skill` → `load_skills` for consistency with
`load_tools`

### Token usage reduction
- Output serialization layer: strips null/undefined/empty values from
tool results
- Lowered default `find_*` limit from 100 → 10, max from 1000 → 100

### System object tool generation
- System objects (calendar events, messages, etc.) now generate AI tools
- Only workflow-related and favorite-related objects are excluded

### Context window display fix
- **Bug**: UI compared cumulative tokens (sum of all turns) against
single-request context window → showed 100% after a few turns
- **Fix**: Track `conversationSize` (last step's `inputTokens`) which
represents the actual conversation history size sent to the model
- New `conversationSize` column on thread entity with migration

### Workspace AI instructions
- Support for custom workspace-level AI instructions

---------

Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>

packages/twenty-server/src/modules/workflow/workflow-tools/services/workflow-tool.workspace-service.ts

@@ -3,7 +3,6 @@ import { Injectable } from '@nestjs/common';
 import { type ToolSet } from 'ai';
 
 import { RecordPositionService } from 'src/engine/core-modules/record-position/services/record-position.service';
-import { PerObjectToolGeneratorService } from 'src/engine/core-modules/tool-generator/services/per-object-tool-generator.service';
 import { GlobalWorkspaceOrmManager } from 'src/engine/twenty-orm/global-workspace-datasource/global-workspace-orm.manager';
 import { type RolePermissionConfig } from 'src/engine/twenty-orm/types/role-permission-config';
 import { WorkflowSchemaWorkspaceService } from 'src/modules/workflow/workflow-builder/workflow-schema/workflow-schema.workspace-service';
@@ -11,10 +10,6 @@ import { WorkflowVersionEdgeWorkspaceService } from 'src/modules/workflow/workfl
 import { WorkflowVersionStepHelpersWorkspaceService } from 'src/modules/workflow/workflow-builder/workflow-version-step/workflow-version-step-helpers.workspace-service';
 import { WorkflowVersionStepWorkspaceService } from 'src/modules/workflow/workflow-builder/workflow-version-step/workflow-version-step.workspace-service';
 import { WorkflowVersionWorkspaceService } from 'src/modules/workflow/workflow-builder/workflow-version/workflow-version.workspace-service';
-import {
-  createWorkflowStepToolsFactory,
-  type WorkflowStepToolsDeps,
-} from 'src/modules/workflow/workflow-tools/factories/workflow-step-tools.factory';
 import { createActivateWorkflowVersionTool } from 'src/modules/workflow/workflow-tools/tools/activate-workflow-version.tool';
 import { createComputeStepOutputSchemaTool } from 'src/modules/workflow/workflow-tools/tools/compute-step-output-schema.tool';
 import { createCreateCompleteWorkflowTool } from 'src/modules/workflow/workflow-tools/tools/create-complete-workflow.tool';
@@ -34,7 +29,6 @@ import { WorkflowTriggerWorkspaceService } from 'src/modules/workflow/workflow-t
 @Injectable()
 export class WorkflowToolWorkspaceService {
   private readonly deps: WorkflowToolDependencies;
-  private readonly workflowStepToolsDeps: WorkflowStepToolsDeps;
 
   constructor(
     workflowVersionStepService: WorkflowVersionStepWorkspaceService,
@@ -45,7 +39,6 @@ export class WorkflowToolWorkspaceService {
     workflowSchemaService: WorkflowSchemaWorkspaceService,
     globalWorkspaceOrmManager: GlobalWorkspaceOrmManager,
     recordPositionService: RecordPositionService,
-    private readonly perObjectToolGenerator: PerObjectToolGeneratorService,
   ) {
     this.deps = {
       workflowVersionStepService,
@@ -57,10 +50,6 @@ export class WorkflowToolWorkspaceService {
       globalWorkspaceOrmManager,
       recordPositionService,
     };
-
-    this.workflowStepToolsDeps = {
-      workflowVersionStepService,
-    };
   }
 
   // Generates static workflow tools that don't depend on workspace objects
@@ -136,22 +125,4 @@ export class WorkflowToolWorkspaceService {
       [getWorkflowCurrentVersion.name]: getWorkflowCurrentVersion,
     };
   }
-
-  // Generates dynamic step configurator tools for each workspace object
-  async generateRecordStepConfiguratorTools(
-    workspaceId: string,
-    rolePermissionConfig: RolePermissionConfig,
-  ): Promise<ToolSet> {
-    const workflowStepToolsFactory = createWorkflowStepToolsFactory(
-      this.workflowStepToolsDeps,
-    );
-
-    return this.perObjectToolGenerator.generate(
-      {
-        workspaceId,
-        rolePermissionConfig,
-      },
-      [workflowStepToolsFactory],
-    );
-  }
 }