Apply staged configuration to active

Cancel's any existing rendering operations and applies the staged zone set. If the staged set is empty, the active zone set will be removed upon reinitialization. If necessary zones will be rendered. Rendering is performed asynchronously and rendering time depends on the complexity of the zone set. Clients may query the Zone Monitor status endpoint (GET /api/v1/zone_monitor/status) to check rendering progress. **To delete all zones** (return to zone-free state): 1. Ensuring the staged configuration does not enable Zone Monitor output: - Set `udp_profile_lidar` to a profile other than ZONE16 (e.g., RNG19_RFL8_SIG16_NIR16_DUAL) - Set `udp_dest_zm` to "" AND/OR set `udp_port_zm` to 0 2. DELETE /api/v1/zone_monitor/staged (clears the staged configuration) 3. POST /api/v1/zone_monitor/apply (applies empty staged, deleting active zones) The apply endpoint will return the empty zone set hash and Zone Monitor will be disabled after reinitialization. **Note**: Empty zone sets (zones: {}) cannot be uploaded via ZIP. Deletion requires the three-step process above. **Important**: Zone Monitor must be disabled (in the staged configuration) before deleting zones. Attempting to delete zones while Zone Monitor is enabled will result in a 400 error with a descriptive message explaining the requirement.