Clarify registry tools vs native model tool binding (#20022)

## Intent

This is a small foundation cleanup for the tool architecture.

The main decision is: registry tools and native SDK/model tools are
different things.

- Registry tools have descriptors, schemas, catalog entries, and execute
through `ToolExecutorService`
- Native model tools are opaque AI SDK objects, bound directly into the
model `ToolSet`
- Surfaces still own their policy: chat, MCP, and workflow agents decide
what they expose

## What changed

- Removed `NATIVE_MODEL` from `ToolCategory`
- Kept `ToolRegistryService` focused on registry-backed tools only
- Moved native model tool binding through `NativeToolBinderService`
- Reused native binding from chat instead of duplicating
provider-specific web-search logic
- Kept MCP local execution exclusions in a dedicated constant
- Moved surface-specific constants into dedicated constant files

## What comes next

- Move hardcoded chat app preloads, like Exa web search, into
app/manifest metadata
- Decide a clearer policy for local runtime tools like code interpreter
and HTTP request
- Gradually document the three tool shapes: registry tools, native model
tools, and local runtime tools

---------

Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: Félix Malfait <FelixMalfait@users.noreply.github.com>
Co-authored-by: Félix Malfait <felix.malfait@gmail.com>

packages/twenty-server/src/engine/api/mcp/constants/mcp-excluded-tool-names.const.ts

@@ -0,0 +1,4 @@
+export const MCP_EXCLUDED_TOOL_NAMES = new Set([
+  'code_interpreter',
+  'http_request',
+]);

packages/twenty-server/src/engine/api/mcp/services/mcp-protocol.service.ts

@@ -4,6 +4,7 @@ import { type ToolSet, zodSchema } from 'ai';
 import { isDefined } from 'twenty-shared/utils';
 
 import { JSON_RPC_ERROR_CODE } from 'src/engine/api/mcp/constants/json-rpc-error-code.const';
+import { MCP_EXCLUDED_TOOL_NAMES } from 'src/engine/api/mcp/constants/mcp-excluded-tool-names.const';
 import { MCP_PROTOCOL_VERSION } from 'src/engine/api/mcp/constants/mcp-protocol-version.const';
 import { MCP_SERVER_INFO } from 'src/engine/api/mcp/constants/mcp-server-info.const';
 import { MCP_SERVER_INSTRUCTIONS } from 'src/engine/api/mcp/constants/mcp-server-instructions.const';
@@ -40,8 +41,6 @@ import { type FlatWorkspace } from 'src/engine/core-modules/workspace/types/flat
 import { SkillService } from 'src/engine/metadata-modules/skill/skill.service';
 import { UserRoleService } from 'src/engine/metadata-modules/user-role/user-role.service';
 
-const MCP_EXCLUDED_TOOLS = new Set(['code_interpreter', 'http_request']);
-
 @Injectable()
 export class McpProtocolService {
   constructor(
@@ -127,7 +126,7 @@ export class McpProtocolService {
         ...createGetToolCatalogTool(this.toolRegistry, workspace.id, roleId, {
           userId: options?.userId,
           userWorkspaceId: options?.userWorkspaceId,
-          excludeTools: MCP_EXCLUDED_TOOLS,
+          excludeTools: MCP_EXCLUDED_TOOL_NAMES,
         }),
         inputSchema: zodSchema(getToolCatalogInputSchema),
       },
@@ -135,13 +134,13 @@ export class McpProtocolService {
         ...createLearnToolsTool(
           this.toolRegistry,
           toolContext,
-          MCP_EXCLUDED_TOOLS,
+          MCP_EXCLUDED_TOOL_NAMES,
         ),
         inputSchema: zodSchema(learnToolsInputSchema),
       },
       [EXECUTE_TOOL_TOOL_NAME]: {
         ...createExecuteToolTool(this.toolRegistry, toolContext, {
-          excludeTools: MCP_EXCLUDED_TOOLS,
+          excludeTools: MCP_EXCLUDED_TOOL_NAMES,
         }),
         inputSchema: executeToolInputSchema,
       },