docs: add git workflow guidelines for sequential command execution

PROJECT_GUIDELINES.md

@@ -47,8 +47,14 @@
 - ❌ **NEVER delete code without reading full context first** (minimum 20 lines before/after)
 - ❌ **NEVER make cascading fix-up edits without git diff review**
   - After compilation error: STOP, review `git diff`, understand full impact
-  - Use revert/re-apply pattern instead of blind fixes
+  - Use revert/reapply pattern instead of blind fixes
 - ❌ **NEVER skip post-edit verification** - must compile after each file edit
+- ❌ **NEVER run git commands concurrently** - always run sequentially:
+  - Run `git add <files>` and wait for completion
+  - Run `git commit -m "<message>"` and wait for completion
+  - Run `git push` and wait for completion
+  - Never use `&&` to chain git commands together
+- ✅ **Make good organized git commits for the entire project (not just what you changed) and push - run git add, commit, push sequentially as separate commands, no need to repeatedly check status**
 
 ### Cascading Fix-up Pattern (PROHIBITED)