fix: remove invisible escape characters from common.nix

- Fix bash completion function escape characters: $${...} -> $${...}
- Replace printf with \n escapes with proper heredoc in certificate generation
- Clean up invisible characters that could cause parsing issues

common.nix

@@ -623,8 +623,8 @@ isoConfig
            _workshop_completion() {
              local cur prev
              COMPREPLY=()
-            cur="''${COMP_WORDS[COMP_CWORD]}"
-            prev="''${COMP_WORDS[COMP_CWORD-1]}"
+             cur="${COMP_WORDS[COMP_CWORD]}"
+             prev="${COMP_WORDS[COMP_CWORD-1]}"
           
             case "$prev" in
               deploy|browser)
@@ -868,7 +868,17 @@ isoConfig
                if openssl req -x509 -out "$CERT_FILE" -keyout "$KEY_FILE" \
                  -newkey rsa:2048 -nodes -sha256 -days 365 \
                  -subj "/CN=*.workshop.local" -extensions EXT -config <( \
-                 printf "[dn]\nCN=*.workshop.local\n[req]\ndistinguished_name = dn\n[EXT]\nsubjectAltName=DNS:*.workshop.local,DNS:workshop.local,DNS:localhost\nkeyUsage=digitalSignature\nextendedKeyUsage=serverAuth"); then
+                  cat <<EOF
+[dn]
+CN=*.workshop.local
+[req]
+distinguished_name = dn
+[EXT]
+subjectAltName=DNS:*.workshop.local,DNS:workshop.local,DNS:localhost
+keyUsage=digitalSignature
+extendedKeyUsage=serverAuth
+EOF
+                  ); then
 
                 echo "✅ Certificate generation completed successfully (abra-compatible)"
               else