[Bug] SSL: CERTIFICATE_VERIFY_FAILED when installing nodes in ComfyUI Manager (Windows Portable)

**Describe the bug**
When trying to install missing components or nodes using ComfyUI Manager in the Windows portable version, installation fails with an SSL certificate verification error:

This happens because the embedded Python in `ComfyUI_windows_portable` is not configured to use an up-to-date CA certificate bundle.

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**Environment:**
- OS: Windows 10/11
- ComfyUI Version: (Portable, NVIDIA build)
- Python: Embedded (comes with ComfyUI portable)

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**Steps to reproduce:**
1. Use ComfyUI Windows Portable
2. Open ComfyUI Manager
3. Try to install/update a node from CDN (e.g., `cdn.comfy.org`)
4. Installation fails with SSL error

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**Solution / Workaround:**

The fix is to point the embedded Python to the existing `certifi` CA bundle:

1. Open Command Prompt
2. Run:

setx SSL_CERT_FILE "\python_embeded\Lib\site-packages\certifi\cacert.pem"

3. Restart ComfyUI

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**Why this works:**
The embedded Python ships with `certifi`, which has a current CA store, but by default it may not be used.
Setting the `SSL_CERT_FILE` environment variable forces Python to use the correct certificate bundle, allowing HTTPS downloads to succeed.

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**Possible improvement:**
- Have ComfyUI Manager automatically detect and use the `certifi` CA bundle in the embedded Python environment.
- Or bundle updated CA certs by default and point `SSL_CERT_FILE` on startup.