chore: clean up old plan files and update gitignore

- Add build artifacts to .gitignore (binaries/, *.exe, *.pdb)
- Update WORK_SUMMARY with latest progress
- Remove outdated plan files (moved to docs/archive/plans/)

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

.gitignore

@@ -35,3 +35,8 @@ Thumbs.db
 # Tauri
 desktop/src-tauri/target/
 desktop/dist/
+# Build artifacts
+desktop/src-tauri/binaries/
+*.exe
+*.pdb
+