chore: ignore root-level *.md and *.txt files (except README.md)

Prevent accidental commits of documentation/analysis files
that should remain local working notes, not tracked in git.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: tsafin

.gitignore

@@ -69,6 +69,11 @@ __pycache__/
 *.deb
 *.rpm
 
+# Root-level documentation and text files (except README.md)
+/*.md
+!README.md
+/*.txt
+
 # Rust build artifacts
 # Note: Cargo target directory should be in CMAKE_BINARY_DIR (e.g., build/rust/)
 # NOT in the source tree. Ignore any in-source target/ directories.