fix: Resolve compilation errors in parallel and cache modules

- Fix parallel execution logic to properly handle JoinHandle<Result<R, E>> types
- Use join_all instead of try_join_all for proper Result handling
- Fix double question mark (??) issue in parallel execution methods
- Clean up unused imports in parallel and cache modules
- Ensure all performance optimization modules compile successfully
- Fix CI build failures caused by compilation errors

scripts/validate-compatibility.sh

@@ -0,0 +1,122 @@
+#!/bin/bash
+
+# apt-ostree Compatibility Validator
+# Tests CLI compatibility with rpm-ostree
+
+set -e
+
+echo "🔍 Validating apt-ostree compatibility with rpm-ostree..."
+echo "=================================================="
+
+# Check if both commands are available
+if ! command -v rpm-ostree &> /dev/null; then
+    echo "❌ rpm-ostree not found. Install it first for comparison."
+    exit 1
+fi
+
+if ! command -v apt-ostree &> /dev/null; then
+    echo "❌ apt-ostree not found. Build it first with 'cargo build --release'"
+    exit 1
+fi
+
+echo "✅ Both commands available"
+
+# Test command structure
+echo ""
+echo "📋 Testing command structure..."
+
+# Get command lists
+rpm_ostree_commands=$(rpm-ostree --help 2>/dev/null | grep -E "^  [a-z-]+" | awk '{print $1}' | sort)
+apt_ostree_commands=$(apt-ostree --help 2>/dev/null | grep -E "^  [a-z-]+" | awk '{print $1}' | sort)
+
+echo "rpm-ostree commands: $(echo "$rpm_ostree_commands" | wc -l)"
+echo "apt-ostree commands: $(echo "$apt_ostree_commands" | wc -l)"
+
+# Find missing commands
+missing_commands=$(comm -23 <(echo "$rpm_ostree_commands") <(echo "$apt_ostree_commands"))
+extra_commands=$(comm -13 <(echo "$rpm_ostree_commands") <(echo "$apt_ostree_commands"))
+
+if [ -n "$missing_commands" ]; then
+    echo "❌ Missing commands:"
+    echo "$missing_commands" | sed 's/^/  - /'
+else
+    echo "✅ All rpm-ostree commands are available"
+fi
+
+if [ -n "$extra_commands" ]; then
+    echo "ℹ️  Extra commands:"
+    echo "$extra_commands" | sed 's/^/  + /'
+fi
+
+# Test help command compatibility
+echo ""
+echo "📖 Testing help command compatibility..."
+
+# Compare help output structure
+rpm_help_lines=$(rpm-ostree --help 2>/dev/null | wc -l)
+apt_help_lines=$(apt-ostree --help 2>/dev/null | wc -l)
+
+echo "rpm-ostree help lines: $rpm_help_lines"
+echo "apt-ostree help lines: $apt_help_lines"
+
+# Test basic command execution
+echo ""
+echo "🧪 Testing basic command execution..."
+
+# Test status command
+echo "Testing 'status' command..."
+if apt-ostree status &>/dev/null; then
+    echo "✅ Status command works"
+else
+    echo "❌ Status command failed"
+fi
+
+# Test help command
+echo "Testing '--help' flag..."
+if apt-ostree --help &>/dev/null; then
+    echo "✅ Help flag works"
+else
+    echo "❌ Help flag failed"
+fi
+
+# Test version command
+echo "Testing '--version' flag..."
+if apt-ostree --version &>/dev/null; then
+    echo "✅ Version flag works"
+else
+    echo "❌ Version flag failed"
+fi
+
+# Test invalid command handling
+echo ""
+echo "⚠️  Testing error handling..."
+
+# Test invalid command
+echo "Testing invalid command..."
+if apt-ostree invalid-command &>/dev/null; then
+    echo "❌ Invalid command should have failed"
+else
+    echo "✅ Invalid command properly rejected"
+fi
+
+# Test invalid flag
+echo "Testing invalid flag..."
+if apt-ostree --invalid-flag &>/dev/null; then
+    echo "❌ Invalid flag should have failed"
+else
+    echo "✅ Invalid flag properly rejected"
+fi
+
+echo ""
+echo "🎯 Compatibility validation complete!"
+echo ""
+echo "Summary:"
+echo "- Commands available: $(echo "$apt_ostree_commands" | wc -l)/$(echo "$rpm_ostree_commands" | wc -l)"
+echo "- Missing: $(echo "$missing_commands" | wc -l)"
+echo "- Extra: $(echo "$extra_commands" | wc -l)"
+
+if [ -z "$missing_commands" ]; then
+    echo "🎉 100% command compatibility achieved!"
+else
+    echo "⚠️  Some commands still need implementation"
+fi