Bundle LZMA SDK for .edz extraction; drop 7z CLI dependency (M3)

Replaces the QProcess->7z shim with the public-domain LZMA SDK (23.01) 7-Zip
reader, vendored under sources/import/edz/lzma/ (decode-only subset). New
edzsevenzip.cpp wraps SzArEx_Open/SzArEx_Extract and writes entries via Qt, so
EdzArchive no longer needs an external 7-Zip at runtime. Enables the C language
in CMake for the vendored sources.

Verified: the bundled decoder extracts all three ifm sample .edz and the
generated elements still match the Python oracle exactly (byte-correct decode),
with no 7z on the path.

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

sources/import/edz/lzma/Sha256.h

@@ -0,0 +1,76 @@
+/* Sha256.h -- SHA-256 Hash
+2023-04-02 : Igor Pavlov : Public domain */
+
+#ifndef ZIP7_INC_SHA256_H
+#define ZIP7_INC_SHA256_H
+
+#include "7zTypes.h"
+
+EXTERN_C_BEGIN
+
+#define SHA256_NUM_BLOCK_WORDS  16
+#define SHA256_NUM_DIGEST_WORDS  8
+
+#define SHA256_BLOCK_SIZE   (SHA256_NUM_BLOCK_WORDS * 4)
+#define SHA256_DIGEST_SIZE  (SHA256_NUM_DIGEST_WORDS * 4)
+
+typedef void (Z7_FASTCALL *SHA256_FUNC_UPDATE_BLOCKS)(UInt32 state[8], const Byte *data, size_t numBlocks);
+
+/*
+  if (the system supports different SHA256 code implementations)
+  {
+    (CSha256::func_UpdateBlocks) will be used
+    (CSha256::func_UpdateBlocks) can be set by
+       Sha256_Init()        - to default (fastest)
+       Sha256_SetFunction() - to any algo
+  }
+  else
+  {
+    (CSha256::func_UpdateBlocks) is ignored.
+  }
+*/
+
+typedef struct
+{
+  SHA256_FUNC_UPDATE_BLOCKS func_UpdateBlocks;
+  UInt64 count;
+  UInt64 _pad_2[2];
+  UInt32 state[SHA256_NUM_DIGEST_WORDS];
+
+  Byte buffer[SHA256_BLOCK_SIZE];
+} CSha256;
+
+
+#define SHA256_ALGO_DEFAULT 0
+#define SHA256_ALGO_SW      1
+#define SHA256_ALGO_HW      2
+
+/*
+Sha256_SetFunction()
+return:
+  0 - (algo) value is not supported, and func_UpdateBlocks was not changed
+  1 - func_UpdateBlocks was set according (algo) value.
+*/
+
+BoolInt Sha256_SetFunction(CSha256 *p, unsigned algo);
+
+void Sha256_InitState(CSha256 *p);
+void Sha256_Init(CSha256 *p);
+void Sha256_Update(CSha256 *p, const Byte *data, size_t size);
+void Sha256_Final(CSha256 *p, Byte *digest);
+
+
+
+
+// void Z7_FASTCALL Sha256_UpdateBlocks(UInt32 state[8], const Byte *data, size_t numBlocks);
+
+/*
+call Sha256Prepare() once at program start.
+It prepares all supported implementations, and detects the fastest implementation.
+*/
+
+void Sha256Prepare(void);
+
+EXTERN_C_END
+
+#endif