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.

apt-dnf-bridge/Cargo.toml

@@ -0,0 +1,37 @@
+[package]
+name = "apt-dnf-bridge"
+version.workspace = true
+edition.workspace = true
+description = "DNF-like API for APT, with optional advanced features"
+license.workspace = true
+repository.workspace = true
+keywords.workspace = true
+categories.workspace = true
+
+[dependencies]
+apt-dnf-bridge-core = { path = "../apt-dnf-bridge-core" }
+apt-dnf-bridge-advanced = { path = "../apt-dnf-bridge-advanced", optional = true }
+tokio = { workspace = true, features = ["macros", "rt-multi-thread"] }
+
+[features]
+default = []  # Core-only by default
+advanced = ["apt-dnf-bridge-advanced"]
+
+[dev-dependencies]
+tempfile.workspace = true
+
+[[example]]
+name = "basic_usage"
+path = "../examples/basic_usage.rs"
+
+[[example]]
+name = "package_query"
+path = "../examples/package_query.rs"
+
+[[example]]
+name = "atomicity_notes"
+path = "../examples/atomicity_notes.rs"
+
+[[example]]
+name = "backend_selection"
+path = "../examples/backend_selection.rs"

apt-dnf-bridge/src/lib.rs

@@ -0,0 +1,47 @@
+//! # APT-DNF Bridge
+//!
+//! A DNF-like bridge around APT for apt-ostree integration.
+//! This crate provides a transaction-based API that makes APT work like DNF.
+//!
+//! ## Quick Start
+//!
+//! Core (minimal, shell-out only):
+//! ```toml
+//! apt-dnf-bridge = "0.1"
+//! ```
+//!
+//! With advanced features (pluggable backends, caching):
+//! ```toml
+//! apt-dnf-bridge = { version = "0.1", features = ["advanced"] }
+//! ```
+//!
+//! ## Example
+//!
+//! ```rust,no_run
+//! use apt_dnf_bridge::{Transaction, Package, Repository};
+//!
+//! #[tokio::main]
+//! async fn main() -> Result<(), Box<dyn std::error::Error>> {
+//!     // Create a transaction
+//!     let mut tx = Transaction::new();
+//!
+//!     // Add packages to install
+//!     let vim = Package::new("vim", "2:8.1.2269-1ubuntu5.14", "amd64");
+//!     tx.add_install(vim).await?;
+//!
+//!     // Resolve dependencies (APT handles automatically)
+//!     tx.resolve().await?;
+//!
+//!     // Commit the transaction
+//!     tx.commit().await?;
+//!
+//!     Ok(())
+//! }
+//! ```
+
+// Always expose the core API
+pub use apt_dnf_bridge_core::*;
+
+// Conditionally expose advanced features
+#[cfg(feature = "advanced")]
+pub use apt_dnf_bridge_advanced::*;