Initial commit: APT-DNF Bridge workspace

- Core crate: Minimal shell-out implementation
- Advanced crate: Pluggable backends and enhanced features
- Main crate: Re-exports core + optional advanced features
- Feature flags: Users choose complexity level
- Examples: Working demonstrations of both approaches
- Documentation: Clear README explaining the structure

Implements the refined two-crate approach with workspace + feature flags.

examples/basic_usage.rs

@@ -0,0 +1,54 @@
+//! Basic usage example for the APT-DNF Bridge crate.
+
+use apt_dnf_bridge::{Package, Repository, Transaction};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    println!("APT-DNF Bridge - Basic Usage Example");
+    println!("=================================");
+
+    // Create a package
+    let vim = Package::new("vim", "2:8.1.2269-1ubuntu5.14", "amd64");
+    println!("Created package: {}", vim.spec());
+
+    // Create a transaction with logging enabled
+    let mut tx = Transaction::new_with_logging();
+    println!("Created empty transaction with logging enabled");
+
+    // Add operations to the transaction
+    tx.add_install(vim.clone()).await?;
+    println!("Added install operation for: {}", vim.name);
+
+    // Check transaction status
+    println!("Transaction has {} operations", tx.len());
+    println!("Transaction is empty: {}", tx.is_empty());
+
+    // Note: In a real scenario, you would call:
+    // tx.resolve().await?;  // Resolve dependencies
+    // tx.commit().await?;   // Commit the transaction
+    
+    // But for this example, we'll just show the structure
+    println!("Transaction operations:");
+    for (i, op) in tx.operations().iter().enumerate() {
+        match op {
+            apt_dnf_bridge::Operation::Install(pkg) => {
+                println!("  {}: Install {}", i + 1, pkg.name);
+            }
+            apt_dnf_bridge::Operation::Remove(pkg) => {
+                println!("  {}: Remove {}", i + 1, pkg.name);
+            }
+            apt_dnf_bridge::Operation::Upgrade(pkg) => {
+                println!("  {}: Upgrade {}", i + 1, pkg.name);
+            }
+        }
+    }
+
+    // Create a repository
+    let mut repo = Repository::new("debian", "http://deb.debian.org/debian")?;
+    repo.add_component("main");
+    repo.add_component("contrib");
+    println!("Created repository: {} at {}", repo.name, repo.url);
+    println!("Components: {:?}", repo.components);
+
+    Ok(())
+}