[core] Support block-compressed NSZ and XCZ (#4552)

- [x] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions).
- [x] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md).
- [x] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability.

-------------------
- Add NCZBLOCK (nsz -B / .xcz) reader: each read decodes only the covered blocks and re-encrypts CTR sections, no disk output.
- Allow installing solid .nsz to NAND via DecompressNCZForInstall (lazy, incremental decode with frontier, O(n) instead of O(n^2)).
- Accept BKTR updates with thousands of sections (MaxSectionCount = 0x10000).
- Wire .nsz/.xcz into loader, registered cache, scanner, and NAND install (content_manager.h), and reject solid NCZ from the game list.
- Bump the pinned zstd to 33618c8 in cpmfile.json, which includes the upstream AArch64 revert ([33618c89](https://github.com/facebook/zstd/commit/33618c89e511637f8a6ef955b3501766d71feb53)) for a ZSTD_decodeSequence branch optimization that could corrupt data on ARM64; without it, solid NCZ decoding on Android fails with "Data corruption detected".

NCZ format and CTR counter semantics follow the reference nsz tool and its
Rust port:
- https://github.com/nicoboss/nsz (Decompressor.py, BlockDecompressorReader.py)
- https://docs.rs/nsz-rs/0.3.0/src/nsz_rs/decompress.rs.html

The last-block edge case (decompressed size is an exact multiple of block
size) is handled as described in https://github.com/nicoboss/nsz/issues/210

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4552
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: Shinmegumi <shinmegumi@eden-emu.dev>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/core/loader/nsp.cpp b/src/core/loader/nsp.cpp
index cfc908b4ef..8b2c79394d 100644
--- a/src/core/loader/nsp.cpp
+++ b/src/core/loader/nsp.cpp
@@ -56,6 +56,17 @@ AppLoader_NSP::AppLoader_NSP(FileSys::VirtualFile file_,
 AppLoader_NSP::~AppLoader_NSP() = default;
 
 FileType AppLoader_NSP::IdentifyType(const FileSys::VirtualFile& nsp_file) {
+    // .nsz is NSP-compatible; return NSZ so the game list shows the right type.
+    if (nsp_file->GetName().ends_with(".nsz")) {
+        return FileType::NSZ;
+    }
+
+    // PFS0-shaped .xcz containers are handled by this loader too; report XCZ so the game
+    // list does not show them as NSP. XCI-shaped .xcz is identified by AppLoader_XCI.
+    if (nsp_file->GetName().ends_with(".xcz")) {
+        return FileType::XCZ;
+    }
+
     const FileSys::NSP nsp(nsp_file);
 
     if (nsp.GetStatus() != ResultStatus::Success) {