[Rust] Implement FPU/VMX128 opcodes, XEX LZX decompression, XISO browsing, and memory safety

Major additions to the xenia-rs Rust port:

- CPU: ~170 new PPC opcode implementations (FPU, VMX128, 64-bit ALU, load/store variants)
- XEX: Full LZX (normal) decompression pipeline with AES-128-CBC decryption via mspack FFI
- XEX: Parse file format info, import libraries, and security info AES key from headers
- VFS: Rewrite XISO disc image to use seek-based I/O (handles 7GB+ images without loading into memory)
- App: Auto-detect ISO files and extract default.xex for all CLI commands
- App: Add `info` and `browse` CLI subcommands
- Kernel: Expand HLE exports from 14 to 40 stubs (memory, threading, TLS, I/O, video)
- Memory: Add bounds checking on all guest memory accesses to prevent segfaults
- Types: Add Vec128 array-based accessors (from_u32x4_array, from_f32x4_array, etc.)

Tested against Project Sylpheed (USA) disc image - all four CLI commands
(browse, info, disasm, exec) work correctly.

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

xenia-rs/crates/xenia-xex/build.rs

@@ -0,0 +1,18 @@
+fn main() {
+    let mspack_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+        .join("..")
+        .join("..")
+        .join("..")
+        .join("third_party")
+        .join("mspack");
+
+    cc::Build::new()
+        .file("lzx_wrapper.c")
+        .file(mspack_dir.join("lzxd.c"))
+        .file(mspack_dir.join("system.c"))
+        .include(&mspack_dir)
+        .define("HAVE_CONFIG_H", None)
+        .define("SIZEOF_OFF_T", "8")
+        .warnings(false)
+        .compile("mspack_lzx");
+}