chore: normalize line endings (CRLF -> LF)

No content changes: git diff --ignore-all-space over these files is empty.
The churn came from editing on Windows against a repo checked out with LF.

backend/.dockerignore

@@ -1,14 +1,14 @@
-.git
-.github
-.venv
-.venv-api
-PaddleOCR-VL-1.6_Online_Demo/.venv
-**/__pycache__
-**/*.pyc
-.cache
-.python-version
-issues
-*.md
-pfm-web-app/node_modules
-pfm-web-app/.next
-
+.git
+.github
+.venv
+.venv-api
+PaddleOCR-VL-1.6_Online_Demo/.venv
+**/__pycache__
+**/*.pyc
+.cache
+.python-version
+issues
+*.md
+pfm-web-app/node_modules
+pfm-web-app/.next
+