fix(ios): ensure capacitor-assets output dirs exist on fresh clones

Gitignored AppIcon.appiconset and Splash.imageset are absent after clone,
which made `capacitor-assets generate --ios` fail (missing paths and
Contents.json). Add ensure_ios_capacitor_asset_directories in common.sh
to mkdir and seed minimal Contents.json when needed; call it from
build-ios.sh before asset generation and from the build:native npm script.
Document the behavior in ios/.gitignore.

scripts/common.sh

@@ -337,6 +337,27 @@ parse_args() {
     fi
 }
 
+# iOS: capacitor-assets writes into AppIcon.appiconset and Splash.imageset under
+# Assets.xcassets. Those paths are gitignored (generated). On a fresh clone the
+# folders and Contents.json are missing; the tool opens Contents.json before writing
+# PNGs, so we create minimal asset-catalog stubs when absent.
+ensure_ios_capacitor_asset_directories() {
+    local base="ios/App/App/Assets.xcassets"
+    if [ ! -d "$base" ]; then
+        log_warn "Missing $base — cannot prepare iOS asset directories"
+        return 0
+    fi
+    mkdir -p "$base/AppIcon.appiconset" "$base/Splash.imageset"
+    local minimal_contents='{"images":[],"info":{"author":"xcode","version":1}}'
+    if [ ! -f "$base/AppIcon.appiconset/Contents.json" ]; then
+        printf '%s\n' "$minimal_contents" > "$base/AppIcon.appiconset/Contents.json"
+    fi
+    if [ ! -f "$base/Splash.imageset/Contents.json" ]; then
+        printf '%s\n' "$minimal_contents" > "$base/Splash.imageset/Contents.json"
+    fi
+    log_debug "Ensured iOS capacitor-assets output directories exist"
+}
+
 # Export functions for use in child scripts
 export -f log_info log_success log_warn log_error log_debug log_step
 export -f measure_time print_header print_footer
@@ -344,4 +365,5 @@ export -f check_command check_directory check_file
 export -f safe_execute check_venv get_git_hash
 export -f clean_build_artifacts validate_env_vars
 export -f setup_build_env setup_app_directories load_env_file print_env_vars
-export -f print_usage parse_args 
+export -f print_usage parse_args
+export -f ensure_ios_capacitor_asset_directories