feat: add PE image decompression and extraction pipeline (M5)

Implement full decrypt + decompress pipeline for XEX2 PE extraction:
- decompress.rs: None, Basic (zero-fill), and Normal (LZX) decompression
- extract.rs: orchestrates decryption then decompression
- Wire up CLI extract command to write PE files
- LZX decompression via lzxd crate with per-frame chunk processing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main.rs

@@ -45,15 +45,28 @@ fn cmd_inspect(path: &PathBuf) {
 }
 
 fn cmd_extract(path: &PathBuf, output: Option<PathBuf>) {
-    let _output_path = output.unwrap_or_else(|| path.with_extension("exe"));
+    let output_path = output.unwrap_or_else(|| path.with_extension("exe"));
 
     let data = read_file(path);
-    let _xex = parse_xex(&data);
+    let xex = parse_xex(&data);
 
-    // TODO(M5): decrypt + decompress pipeline
-    // TODO(M6): verify PE and write to output_path
-    eprintln!("Error: extraction not yet implemented (coming in M5/M6)");
-    process::exit(1);
+    let pe_image = match xex2tractor::extract::extract_pe_image(&data, &xex) {
+        Ok(img) => img,
+        Err(e) => {
+            eprintln!("Error extracting PE image: {e}");
+            process::exit(1);
+        }
+    };
+
+    // TODO(M6): verify PE headers before writing
+    if let Err(e) = std::fs::write(&output_path, &pe_image) {
+        eprintln!("Error writing {}: {e}", output_path.display());
+        process::exit(1);
+    }
+
+    println!("Extracted PE image to {}", output_path.display());
+    println!("  Input:  {} ({} bytes)", path.display(), data.len());
+    println!("  Output: {} ({} bytes)", output_path.display(), pe_image.len());
 }
 
 fn read_file(path: &PathBuf) -> Vec<u8> {