Remove auto-generated projects.json from git tracking

- Add config/projects.json to .gitignore
- Remove from git tracking while preserving local file
- projects.json is auto-generated by Home Manager from projects.nix
- Prevents merge conflicts and version control noise from machine-specific paths

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.gitignore

@@ -17,3 +17,6 @@ Thumbs.db
 #*#
 *.swp
 *.swo
+
+# Auto-generated files
+config/projects.json

config/projects.json

@@ -1 +0,0 @@
-/nix/store/wra0kir8w2f9g6q6qmy8jwk585vbgavr-home-manager-files/.config/nix/config/projects.json