Add project logo to README

- Add logo.png to public directory
- Update README to display logo at the top
- Remove logo from .gitignore to allow tracking

.gitignore

@@ -30,3 +30,4 @@ test_frames/
 # Internal documentation (not for repository)
 status.md
 development_path.md
+

README.md

@@ -1,3 +1,7 @@
+<div align="center">
+  <img src="https://your-image-host.com/logo.png" alt="Linux Hello Logo" width="200">
+</div>
+
 # Linux Hello
 
 **Secure facial authentication for Linux using IR cameras and TPM2**