Normalize line endings to LF; add .gitattributes and .editorconfig

scripts/normalize_eol.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+#
+# ITFlow - one-shot CRLF -> LF normalization.
+#
+# Converts every tracked text file outside libs/ to LF. Vendored libraries are
+# left byte-for-byte as shipped upstream (CONTRIBUTING.md: libs/ is replaced
+# wholesale, never edited), and binary assets are skipped outright.
+#
+# Run once, from the repo root, alongside adding .gitattributes. After that
+# .gitattributes keeps new files in line and this script should be a no-op.
+#
+set -euo pipefail
+
+cd "$(git rev-parse --show-toplevel)"
+
+BINARY_RE='\.(png|gif|jpg|jpeg|webp|ico|icc|woff|woff2|ttf|eot|crt|ser|z)$'
+
+mapfile -t candidates < <(git ls-files | grep -v '^libs/' | grep -viE "$BINARY_RE")
+
+changed=0
+for f in "${candidates[@]}"; do
+    [ -f "$f" ] || continue
+    # only touch files that actually contain a CR
+    if LC_ALL=C grep -qU $'\r' "$f" 2>/dev/null; then
+        LC_ALL=C sed -i 's/\r$//' "$f"
+        changed=$((changed + 1))
+    fi
+done
+
+echo "normalized $changed file(s)"