Fix CI: drop incorrect -c flag, fix word splitting in tests

build-iso:
- Remove -c flag (it takes a pacman.conf path, not a clean flag)
- Use absolute paths for mkarchiso with -- separator
- Copy local-aur.files* alongside local-aur.db*

tests:
- Fix word splitting: use 'while IFS= read -r' instead of
  'for f in ' for shell and YAML file loops
- Fix YAML find filter to use -not -path like shell find

.gitea/workflows/tests.yaml

@@ -80,7 +80,7 @@ jobs:
           fi
 
           FAILED=0
-          for f in $SH_FILES; do
+          while IFS= read -r f; do
             echo ""
             echo "── Checking: $f"
             if shellcheck -x -s bash "$f"; then
@@ -89,7 +89,7 @@ jobs:
               echo "  ❌ $f failed"
               FAILED=1
             fi
-          done
+          done <<< "$SH_FILES"
 
           if [ "$FAILED" -ne 0 ]; then
             echo ""
@@ -110,14 +110,14 @@ jobs:
           echo "  Running yamllint on all YAML files"
           echo "═══════════════════════════════════════════════════════════════"
 
-          YAML_FILES=$(find . -name '*.yml' -o -name '*.yaml' | grep -v '.git/')
+          YAML_FILES=$(find . -not -path './.git/*' \( -name '*.yml' -o -name '*.yaml' \))
           if [ -z "$YAML_FILES" ]; then
             echo "No YAML files found."
             exit 0
           fi
 
           FAILED=0
-          for f in $YAML_FILES; do
+          while IFS= read -r f; do
             echo ""
             echo "── Checking: $f"
             if yamllint -d "{extends: relaxed, rules: {document-start: disable, line-length: disable, new-line-at-end-of-file: disable}}" "$f"; then
@@ -126,7 +126,7 @@ jobs:
               echo "  ❌ $f failed"
               FAILED=1
             fi
-          done
+          done <<< "$YAML_FILES"
 
           if [ "$FAILED" -ne 0 ]; then
             echo ""