Add Runner Edit/Delete + Admin Toggle

## Overview
Enable runner editing and deletion with admin capabilities for viewing all runners.

## Acceptance Criteria
- [ ] Enable Edit: PUT /api/v1/runners/{id} (ownership check server-side)
- [ ] Enable Delete: DELETE /api/v1/runners/{id} (soft delete if supported)
- [ ] If role=Admin:
- Toggle "All Runners" view (server supplies full list)
- Status filter and pagination visible
- [ ] Non-owner actions return 403 → UI shows "You don't have access"
- [ ] Owner can edit/delete own runners; non-owner blocked
- [ ] Admin can view/manage all runners with filters/pagination

## Test Notes
- Test owner can edit/delete own runners
- Test non-owner cannot edit/delete others' runners
- Test admin can view all runners
- Test admin filters and pagination work correctly

## Implementation Notes
- Implement proper ownership checks on frontend
- Add admin role detection and UI changes
- Implement proper error handling for 403 responses
- Add confirmation dialogs for destructive actions

Start from the runner API endpoints and the runner management UI described in the issue, then trace how ownership and admin roles are currently determined. Verify the existing runner list, status filtering, pagination, and 403 error-handling paths before making changes. Done means owners can edit or delete their runners, non-owners receive the specified message, and admins can manage the full filtered list with confirmation dialogs.

Written by the indexing model from the issue text.