fix: git stash before deploy, no pop (discard board changes)

- just deploy: stash local board changes before git pull
- install.sh: configure git alias 'pull-clean' for manual use
- Board-side changes from test edits are discarded on deploy

justfile

@@ -101,7 +101,7 @@ install:
 deploy:
     @git push origin HEAD 2>&1
     @ssh {{SSH_OPTS}} "{{BOARD_USER}}@{{BOARD_HOST}}" "\
-        cd {{REPO_DIR}} && git pull && \
+        cd {{REPO_DIR}} && git stash && git pull && \
         git config core.hooksPath .githooks && \
         chmod +x scripts/*.py scripts/*.sh 2>/dev/null; \
         echo '{{BOARD_PASS}}' | sudo -S systemctl daemon-reload && \