WIP: frontend clone_mode removal in create form and API

- Remove clone_mode/branch/new_branch from createInstance API helper
- Remove clone mode UI and branch fields from CreateSessionForm

Remaining: wire workspace_id in form/tool-starter, remove session-card badge, tests

apps/api/src/api/workspace/workspace_instances.py

@@ -2,13 +2,16 @@
 
 import uuid
 
-from fastapi import APIRouter, Depends, HTTPException
+from fastapi import APIRouter, Depends, HTTPException, status
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from src.auth.dependencies import get_current_user_id, get_db_session
+from src.models import GitRepository
 from src.models import ToolInstance
 from src.models import Workspace
+from src.schemas.tool import CreateInstanceRequest, CreateWorkspaceInstanceRequest
+from src.services.tool.instance_service import create_tool_instance
 
 router = APIRouter(prefix="/workspaces/{workspace_id}/instances")
 
@@ -30,6 +33,63 @@ async def _get_workspace(
     return workspace
 
 
+@router.post(
+    "/",
+    summary="Create instance from workspace",
+    description="Create a new tool instance mounted on this workspace.",
+    status_code=status.HTTP_201_CREATED,
+)
+async def create_workspace_instance(
+    workspace_id: uuid.UUID,
+    data: CreateWorkspaceInstanceRequest,
+    user_id: uuid.UUID = Depends(get_current_user_id),
+    session: AsyncSession = Depends(get_db_session),
+) -> dict:
+    """Create a tool instance directly on a workspace."""
+    workspace = await _get_workspace(session, workspace_id, user_id)
+
+    repo = await session.get(GitRepository, workspace.repo_id)
+    if repo is None:
+        raise HTTPException(status_code=404, detail="Repository not found")
+    if repo.project_id is None:
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail="Repository is not associated with a project",
+        )
+
+    request = CreateInstanceRequest(
+        tool_type_id=data.tool_type_id,
+        display_name=data.display_name,
+        workspace_id=str(workspace.id),
+        config_profile_id=data.config_profile_id,
+        ssh_key_ids=data.ssh_key_ids,
+    )
+
+    try:
+        instance = await create_tool_instance(
+            session, user_id, repo.project_id, repo.id, request
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc))
+    except RuntimeError as exc:
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=str(exc)
+        )
+
+    return {
+        "id": str(instance.id),
+        "name": instance.name,
+        "display_name": instance.display_name,
+        "tool_type_id": str(instance.tool_type_id),
+        "status": instance.status,
+        "workspace_id": str(instance.workspace_id) if instance.workspace_id else None,
+        "selected_config_profile_id": str(instance.selected_config_profile_id)
+        if instance.selected_config_profile_id
+        else None,
+        "created_at": instance.created_at.isoformat(),
+    }
+
+
 @router.get("/")
 async def list_workspace_instances(
     workspace_id: uuid.UUID,