Fix macOS SSL cert issue, add troubleshooting and upgrade docs

- Add SSL certificate auto-fix in FaceProtector (certifi)
- Add Troubleshooting section to README (SSL, first-run downloads)
- Add upgrade instructions for pipx/uv tool users

README.md

@@ -33,6 +33,14 @@ pipx install git+https://github.com/wiltodelta/remove-ai-watermarks.git
 uv tool install git+https://github.com/wiltodelta/remove-ai-watermarks.git
 ```
 
+To update to the latest version:
+
+```bash
+pipx upgrade remove-ai-watermarks
+# or
+uv tool upgrade remove-ai-watermarks
+```
+
 ### Install from repository (macOS)
 
 **Prerequisites:** Python 3.10+ and `pip` (or [`uv`](https://docs.astral.sh/uv/)).
@@ -137,6 +145,20 @@ if has_ai_metadata(Path("image.png")):
 - **Visible removal / metadata**: CPU only, no GPU required
 - **Invisible removal**: GPU recommended (CUDA or MPS), works on CPU (slow)
 
+## Troubleshooting
+
+**SSL certificate error on macOS** (`CERTIFICATE_VERIFY_FAILED`):
+
+```bash
+# Option 1: Run the Python certificate installer
+/Applications/Python\ 3.*/Install\ Certificates.command
+
+# Option 2: Install certifi (the tool auto-detects it)
+pip install certifi
+```
+
+**First run is slow** — this is expected. The tool downloads model weights (~2 GB) on first launch. Subsequent runs use cached models.
+
 ## Credits
 
 - [noai-watermark](https://github.com/mertizci/noai-watermark) by mertizci — invisible watermark removal engine