Add BSA in-memory extraction and nested preview support

bsatk:
- Archive::extractToMemory() extracts a file directly into a byte buffer
  instead of a filesystem path, backed by a std::ostringstream sink.
- Archive::findFile() locates a file by relative path, case-insensitive
  and separator-agnostic, walking the folder tree recursively.
- extractDirect/extractCompressed now take std::ostream& so both the
  ofstream and ostringstream paths share the same implementation.

libbsarch: shim rewrite on Linux to map the Windows API surface onto
bsatk::Archive, enabling preview_bsa to open vanilla BSAs via the
same interface as other plugins.

preview_bsa: double-click on a file in the BSA tree now extracts the
bytes via extractToMemory() and hands them to IOrganizer::previewFileData
for nested preview rendering (e.g. NIF inside a BSA).

uibase + organizerproxy + organizercore: new IOrganizer::previewFileData
virtual that routes in-memory file bytes through the first registered
IPluginPreview matching the extension. Uses heap + WA_DeleteOnClose +
open() to avoid nested exec() softlock from mod info filetree ->
preview_bsa tree -> nif preview.

docker/build-inner.sh: stage preview_nif shaders into plugin_data/shaders
so ShaderManager can load them via IOrganizer::getPluginDataPath().

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

1 files changed, 19 insertions, 2 deletions

diff --git a/libs/bsatk/include/bsatk/bsaarchive.h b/libs/bsatk/include/bsatk/bsaarchive.h
index cd15f64..915b9fb 100644
--- a/libs/bsatk/include/bsatk/bsaarchive.h
+++ b/libs/bsatk/include/bsatk/bsaarchive.h
@@ -112,6 +112,23 @@ public:
    * @return ERROR_NONE on success or an error code
    */
   EErrorCode extract(File::Ptr file, const char* outputDirectory) const;
+
+  /**
+   * extract a file from the archive directly into an in-memory buffer.
+   * @param file descriptor of the file to extract
+   * @param result output buffer; cleared and filled with uncompressed file data
+   * @return ERROR_NONE on success or an error code
+   */
+  EErrorCode extractToMemory(File::Ptr file,
+                             std::vector<unsigned char>& result) const;
+
+  /**
+   * find a file in the archive by its relative path.
+   * @param path relative path inside the archive (separators may be / or \,
+   *             matching is case-insensitive).
+   * @return the file descriptor, or nullptr if no such file exists.
+   */
+  File::Ptr findFile(const std::string& path) const;
   /**
    * @return archive flags
    */
@@ -211,8 +228,8 @@ private:
   void getDX10Header(DirectX::DDS_HEADER_DXT10& DX10Header, File::Ptr file,
                      DirectX::DDS_HEADER DDSHeader) const;
 
-  EErrorCode extractDirect(File::Ptr file, std::ofstream& outFile) const;
-  EErrorCode extractCompressed(File::Ptr file, std::ofstream& outFile) const;
+  EErrorCode extractDirect(File::Ptr file, std::ostream& outFile) const;
+  EErrorCode extractCompressed(File::Ptr file, std::ostream& outFile) const;
 
   void createFolders(const std::string& targetDirectory, Folder::Ptr folder);