Fix .gitignore - add cmd/server/main.go and use absolute paths for binaries

The pattern 'server' was incorrectly ignoring cmd/server/ directory.
Changed to '/server' to only match root-level compiled binary.

Also committing cmd/server/main.go which was previously ignored.

.gitignore

@@ -4,8 +4,8 @@
 *.dll
 *.so
 *.dylib
-server
-dyn
+/server
+/dyn
 
 # Test binary
 *.test