[GPU,Kernel] RE instrumentation: per-buffer draw log + file-I/O guest map

Draw logger (command_processor.cc): also key each record on the index-buffer
guest base so distinct static index buffers (ship body vs hangar vs weapons) no
longer collapse to one record; dump the first decoded index VALUES + raw index
bytes (8-in-16/32 endian-corrected) and the stream-base hex, to pin an index
buffer's exact .xpr file offset and validate a mesh decode against ground truth.

File-I/O log (xboxkrnl_io.cc): --log_file_io cvar writes each distinct NtReadFile
as 'READ <name> off=.. len=.. -> guest=..' to xenia_re_files.log, giving the
file->guest-memory mapping. Cross-referenced with the draw log's buffer guest
addresses this resolves which .xpr (and where inside it) a mesh loaded from.
De-duped by (offset, guest), capped at 65536 entries.

Also ignore build-cross/ (Wine cross-build output).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitignore

@@ -116,3 +116,6 @@ node_modules/.bin/
 /cache0
 /devkit
 recent.toml
+
+# Cross-compile (Wine) build output — RE handoff, never commit
+build-cross/