Subgraph regression: labels swapped and widget values changed in 1.41.16

## Description

After updating `comfyui-frontend-package` to 1.41.16, subgraphs exhibit two regression bugs: labels are swapped/corrupted and widget values are silently changed when loading existing workflows.

**Reported by:** @jprsyt5 in [Comfy-Org/ComfyUI#12893 (comment)](https://github.com/Comfy-Org/ComfyUI/issues/12893#issuecomment-4046304882)

## Environment

- **Affected version:** `comfyui-frontend-package` 1.41.16
- **Working version:** `comfyui-frontend-package` 1.39.19

## Bug 1: Subgraph labels swapped / corrupted

When loading a workflow containing subgraphs, the exposed widget labels are incorrect.

| Version | Labels |
|---------|--------|
| 1.39.19 | `width` & `height` (correct) |
| 1.41.16 | `a` & `a` (broken) |

**1.39.19 (correct):**

**1.41.16 (broken):**

## Bug 2: Subgraph widget values silently changed

Widget values inside subgraphs are altered upon loading, without any user interaction.

| Widget | 1.39.19 (correct) | 1.41.16 (changed) |
|--------|-------------------|-------------------|
| `context_from_mask_extend_factor` | 1.60 | 1.20 |
| `denoise` | 0.3 | 0.4 |

**`context_from_mask_extend_factor` — 1.39.19 (1.60):**

**`context_from_mask_extend_factor` — 1.41.16 (changed to 1.20):**

**`denoise` — 1.39.19 (0.3):**

**`denoise` — 1.41.16 (changed to 0.4):**

## Steps to reproduce

1. Create or load a workflow containing subgraph nodes with renamed/exposed widgets on `1.39.19`
2. Upgrade to `comfyui-frontend-package` 1.41.16
3. Load the same workflow
4. Observe that subgraph labels are swapped/corrupted and widget values have changed

## Workaround

Unpacking and repacking the subgraph restores correct labels and values, but this must be done manually after every frontend update.

## Impact

This is a **backward compatibility** issue — existing workflows with subgraphs silently break on upgrade. Silent value changes are particularly dangerous as they can produce incorrect generation results without the user noticing.

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-9788-Subgraph-regression-labels-swapped-and-widget-values-changed-in-1-41-16-3216d73d36508132a30ffa871b2ef5ff) by [Unito](https://www.unito.io)