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

src/commands/packages.rs

@@ -0,0 +1,249 @@
+//! Package management commands for apt-ostree
+
+use crate::commands::Command;
+use apt_ostree::lib::error::{AptOstreeError, AptOstreeResult};
+
+/// Install command - Overlay additional packages
+pub struct InstallCommand;
+
+impl InstallCommand {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl Command for InstallCommand {
+    fn execute(&self, args: &[String]) -> AptOstreeResult<()> {
+        if args.contains(&"--help".to_string()) || args.contains(&"-h".to_string()) {
+            self.show_help();
+            return Ok(());
+        }
+        
+        if args.is_empty() {
+            return Err(AptOstreeError::InvalidArgument(
+                "No packages specified. Use --help for usage information.".to_string()
+            ));
+        }
+        
+        let packages: Vec<String> = args.iter()
+            .filter(|arg| !arg.starts_with('-'))
+            .cloned()
+            .collect();
+        
+        if packages.is_empty() {
+            return Err(AptOstreeError::InvalidArgument(
+                "No packages specified. Use --help for usage information.".to_string()
+            ));
+        }
+        
+        println!("📦 Install Packages");
+        println!("===================");
+        println!("Packages to install: {}", packages.join(", "));
+        println!("Status: Placeholder implementation");
+        println!("Next: Implement real package installation logic");
+        
+        Ok(())
+    }
+    
+    fn name(&self) -> &'static str {
+        "install"
+    }
+    
+    fn description(&self) -> &'static str {
+        "Overlay additional packages"
+    }
+    
+    fn show_help(&self) {
+        println!("apt-ostree install - Overlay additional packages");
+        println!();
+        println!("Usage: apt-ostree install <PACKAGES>... [OPTIONS]");
+        println!();
+        println!("Arguments:");
+        println!("  PACKAGES      Package names to install");
+        println!();
+        println!("Options:");
+        println!("  --help, -h    Show this help message");
+    }
+}
+
+/// Uninstall command - Remove overlayed additional packages
+pub struct UninstallCommand;
+
+impl UninstallCommand {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl Command for UninstallCommand {
+    fn execute(&self, args: &[String]) -> AptOstreeResult<()> {
+        if args.contains(&"--help".to_string()) || args.contains(&"-h".to_string()) {
+            self.show_help();
+            return Ok(());
+        }
+        
+        if args.is_empty() {
+            return Err(AptOstreeError::InvalidArgument(
+                "No packages specified. Use --help for usage information.".to_string()
+            ));
+        }
+        
+        let packages: Vec<String> = args.iter()
+            .filter(|arg| !arg.starts_with('-'))
+            .cloned()
+            .collect();
+        
+        if packages.is_empty() {
+            return Err(AptOstreeError::InvalidArgument(
+                "No packages specified. Use --help for usage information.".to_string()
+            ));
+        }
+        
+        println!("🗑️  Uninstall Packages");
+        println!("=====================");
+        println!("Packages to remove: {}", packages.join(", "));
+        println!("Status: Placeholder implementation");
+        println!("Next: Implement real package removal logic");
+        
+        Ok(())
+    }
+    
+    fn name(&self) -> &'static str {
+        "uninstall"
+    }
+    
+    fn description(&self) -> &'static str {
+        "Remove overlayed additional packages"
+    }
+    
+    fn show_help(&self) {
+        println!("apt-ostree uninstall - Remove overlayed additional packages");
+        println!();
+        println!("Usage: apt-ostree uninstall <PACKAGES>... [OPTIONS]");
+        println!();
+        println!("Arguments:");
+        println!("  PACKAGES      Package names to remove");
+        println!();
+        println!("Options:");
+        println!("  --help, -h    Show this help message");
+    }
+}
+
+/// Search command - Search for packages in APT repositories
+pub struct SearchCommand;
+
+impl SearchCommand {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl Command for SearchCommand {
+    fn execute(&self, args: &[String]) -> AptOstreeResult<()> {
+        if args.contains(&"--help".to_string()) || args.contains(&"-h".to_string()) {
+            self.show_help();
+            return Ok(());
+        }
+        
+        // Parse options
+        let mut opt_installed = false;
+        let mut opt_available = false;
+        let mut opt_exact = false;
+        let mut opt_regex = false;
+        let mut opt_show_deps = false;
+        let mut opt_limit = None;
+        let mut query = String::new();
+        
+        let mut i = 0;
+        while i < args.len() {
+            match args[i].as_str() {
+                "--installed" => opt_installed = true,
+                "--available" => opt_available = true,
+                "--exact" => opt_exact = true,
+                "--regex" => opt_regex = true,
+                "--show-deps" => opt_show_deps = true,
+                "--limit" => {
+                    if i + 1 < args.len() {
+                        opt_limit = Some(args[i + 1].clone());
+                        i += 1;
+                    }
+                }
+                _ => {
+                    // First non-option argument is the query
+                    if !args[i].starts_with('-') && query.is_empty() {
+                        query = args[i].clone();
+                    }
+                }
+            }
+            i += 1;
+        }
+        
+        if query.is_empty() {
+            return Err(AptOstreeError::InvalidArgument(
+                "No search query specified. Use --help for usage information.".to_string()
+            ));
+        }
+        
+        println!("🔍 Package Search");
+        println!("=================");
+        println!("Query: {}", query);
+        
+        if opt_installed {
+            println!("Filter: Installed packages only");
+        } else if opt_available {
+            println!("Filter: Available packages only");
+        }
+        
+        if opt_exact {
+            println!("Matching: Exact package name");
+        } else if opt_regex {
+            println!("Matching: Regular expression");
+        }
+        
+        if opt_show_deps {
+            println!("Show dependencies: Enabled");
+        }
+        
+        if let Some(ref limit) = opt_limit {
+            println!("Result limit: {}", limit);
+        }
+        
+        println!("Status: Placeholder implementation");
+        println!("Next: Implement real package search logic");
+        
+        Ok(())
+    }
+    
+    fn name(&self) -> &'static str {
+        "search"
+    }
+    
+    fn description(&self) -> &'static str {
+        "Search for packages in APT repositories"
+    }
+    
+    fn show_help(&self) {
+        println!("apt-ostree search - Search for packages in APT repositories");
+        println!();
+        println!("Usage: apt-ostree search [OPTIONS] <QUERY>");
+        println!();
+        println!("Arguments:");
+        println!("  QUERY                 Search query (package name, description, etc.)");
+        println!();
+        println!("Options:");
+        println!("  --installed            Show only installed packages");
+        println!("  --available            Show only available packages");
+        println!("  --exact                Exact package name matching");
+        println!("  --regex                Regular expression search (not yet implemented)");
+        println!("  --show-deps            Show package dependencies");
+        println!("  --limit <NUMBER>       Limit results to specified number");
+        println!("  --help, -h             Show this help message");
+        println!();
+        println!("Examples:");
+        println!("  apt-ostree search vim");
+        println!("  apt-ostree search --installed vim");
+        println!("  apt-ostree search --exact vim");
+        println!("  apt-ostree search --limit 5 editor");
+        println!("  apt-ostree search --show-deps web server");
+    }
+}