feat: initial implementation of content-addressed incremental backup engine

Rust-centric architecture with TypeScript facade following smartproxy/smartstorage pattern.
Core engine in Rust (FastCDC chunking, SHA-256, gzip, AES-256-GCM + Argon2id, binary pack files,
global index, snapshots, locking, verification, pruning, repair). TypeScript provides npm interface
via @push.rocks/smartrust RustBridge IPC with Unix socket streaming for ingest/restore.
All 14 integration tests pass.

rust/src/main.rs

@@ -0,0 +1,51 @@
+use clap::Parser;
+
+mod config;
+mod error;
+mod management;
+mod chunker;
+mod hasher;
+mod compression;
+mod encryption;
+mod pack_writer;
+mod pack_reader;
+mod global_index;
+mod repository;
+mod snapshot;
+mod lock;
+mod ingest;
+mod restore;
+mod verify;
+mod prune;
+mod repair;
+
+#[derive(Parser, Debug)]
+#[command(name = "containerarchive", about = "Content-addressed incremental backup engine")]
+struct Cli {
+    /// Run in management mode (JSON IPC over stdin/stdout)
+    #[arg(long)]
+    management: bool,
+}
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    // Initialize logging to stderr (stdout is reserved for IPC)
+    tracing_subscriber::fmt()
+        .with_writer(std::io::stderr)
+        .with_env_filter(
+            tracing_subscriber::EnvFilter::from_default_env()
+                .add_directive(tracing::Level::INFO.into()),
+        )
+        .init();
+
+    let cli = Cli::parse();
+
+    if cli.management {
+        management::management_loop().await?;
+    } else {
+        eprintln!("containerarchive: use --management for IPC mode");
+        std::process::exit(1);
+    }
+
+    Ok(())
+}