Initial commit: xenia-rs workspace for Xbox 360 RE

Rust reimplementation of the xenia Xbox 360 emulator targeting reverse-
engineering and preservation, initially scoped to Project Sylpheed.

Includes:
- XEX2 loader (LZX decompression, AES decryption, PE parsing)
- XISO / XGD2 disc image VFS
- PPC interpreter with 200+ opcodes and VMX128 decoding
- Static analyzer: functions, cross-references, labels, asm + SQLite output
- HLE kernel covering the xboxkrnl/xam subset used by Sylpheed init
- Debugger with in-memory and SQLite-backed execution tracing
- `xenia-rs` CLI with extract/dis/exec commands that produce cumulative,
  superset SQLite databases and opt-in instruction/import/branch traces

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

crates/xenia-memory/src/lib.rs

@@ -0,0 +1,31 @@
+pub mod access;
+pub mod heap;
+pub mod mmio;
+pub mod page_table;
+
+mod platform;
+
+use thiserror::Error;
+
+pub use access::MemoryAccess;
+pub use heap::{GuestMemory, HeapType};
+pub use mmio::MmioRegion;
+pub use page_table::PageEntry;
+
+#[derive(Debug, Error)]
+pub enum MemoryError {
+    #[error("Failed to allocate guest address space: {0}")]
+    AllocationFailed(String),
+
+    #[error("Invalid guest address: {0:#010x}")]
+    InvalidAddress(u32),
+
+    #[error("MMIO access at {0:#010x}")]
+    MmioAccess(u32),
+
+    #[error("Protection violation at {0:#010x}")]
+    ProtectionViolation(u32),
+
+    #[error("Out of memory in heap {0:?}")]
+    OutOfMemory(HeapType),
+}