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>

Cargo.lock

@@ -200,6 +200,12 @@ version = "0.2.183"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b5b646652bf6661599e1da8901b3b9522896f01e736bad5f723fe7a3a27f899d"
 
+[[package]]
+name = "lzxd"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7b29dffab797218e12e4df08ef5d15ab9efca2504038b1b32b9b32fc844b39c9"
+
 [[package]]
 name = "once_cell_polyfill"
 version = "1.70.2"
@@ -282,9 +288,10 @@ dependencies = [
 
 [[package]]
 name = "xex2tractor"
-version = "0.4.0"
+version = "0.5.0"
 dependencies = [
  "aes",
  "cbc",
  "clap",
+ "lzxd",
 ]