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/lib/apt.rs

@@ -0,0 +1,108 @@
+use crate::lib::error::{AptOstreeError, AptOstreeResult};
+
+/// Basic APT functionality
+pub struct AptManager {
+    // TODO: Add APT manager fields
+}
+
+impl AptManager {
+    /// Create a new APT manager instance
+    pub fn new() -> Self {
+        Self {}
+    }
+    
+    /// Check APT database health
+    pub fn check_database_health(&self) -> AptOstreeResult<bool> {
+        // TODO: Implement real APT database health check
+        Ok(true)
+    }
+
+    /// Install a package
+    pub async fn install_package(&self, package: &str) -> AptOstreeResult<()> {
+        // TODO: Implement real package installation
+        tracing::info!("Installing package: {}", package);
+        Ok(())
+    }
+
+    /// Remove a package
+    pub async fn remove_package(&self, package: &str) -> AptOstreeResult<()> {
+        // TODO: Implement real package removal
+        tracing::info!("Removing package: {}", package);
+        Ok(())
+    }
+
+    /// Update package cache
+    pub fn update_cache(&self) -> AptOstreeResult<()> {
+        // TODO: Implement real cache update
+        tracing::info!("Updating package cache");
+        Ok(())
+    }
+
+    /// Check if authorization is required for an action
+    pub fn requires_authorization(&self, action: &str) -> bool {
+        // TODO: Implement real authorization requirement check
+        tracing::info!("Checking if authorization required for: {}", action);
+        true
+    }
+
+    /// Check if user is authorized for an action
+    pub async fn check_authorization(&self, action: &str) -> AptOstreeResult<bool> {
+        // TODO: Implement real authorization check
+        tracing::info!("Checking authorization for: {}", action);
+        Ok(true)
+    }
+
+    /// Search packages with exact match
+    pub fn search_packages_exact(&self, query: &str) -> AptOstreeResult<Vec<PackageInfo>> {
+        // TODO: Implement real exact search
+        tracing::info!("Searching packages exactly: {}", query);
+        Ok(vec![PackageInfo::new(query)])
+    }
+
+    /// Search packages with regex
+    pub fn search_packages_regex(&self, query: &str) -> AptOstreeResult<Vec<PackageInfo>> {
+        // TODO: Implement real regex search
+        tracing::info!("Searching packages with regex: {}", query);
+        Ok(vec![PackageInfo::new(query)])
+    }
+
+    /// Search packages
+    pub fn search_packages(&self, query: &str) -> AptOstreeResult<Vec<PackageInfo>> {
+        // TODO: Implement real search
+        tracing::info!("Searching packages: {}", query);
+        Ok(vec![PackageInfo::new(query)])
+    }
+
+    /// Check if a package is installed
+    pub fn is_package_installed(&self, package: &str) -> AptOstreeResult<bool> {
+        // TODO: Implement real package installation check
+        tracing::info!("Checking if package is installed: {}", package);
+        Ok(false)
+    }
+}
+
+/// Package information
+#[derive(Debug, Clone)]
+pub struct PackageInfo {
+    pub name: String,
+    pub version: String,
+    pub description: String,
+    pub installed: bool,
+    pub section: String,
+    pub priority: String,
+    pub depends: Vec<String>,
+}
+
+impl PackageInfo {
+    pub fn new(name: &str) -> Self {
+        Self {
+            name: name.to_string(),
+            version: "0.0.0".to_string(),
+            description: "Package description".to_string(),
+            installed: false,
+            section: "unknown".to_string(),
+            priority: "optional".to_string(),
+            depends: Vec::new(),
+        }
+    }
+}