feat(rust): port deprecated ZBUFF streaming wrappers

Move the public ZBUFF compatibility layer into the Rust static archive while
keeping stream contexts opaque and forwarding to the current ZSTD streaming
APIs.  The deprecated C translation units are now declaration-only shims, so
the compatibility symbols work in compression-only and decompression-only
feature builds without duplicating private context layouts.

Test Plan:
- cargo test --manifest-path rust/Cargo.toml
- cargo clippy --manifest-path rust/Cargo.toml --all-targets -- -D warnings
- cargo +nightly fmt --manifest-path rust/Cargo.toml -- --check
- make -B -C lib libzstd.a ZSTD_LIB_DEPRECATED=1 V=1
- C ZBUFF compress/decompress smoke test against the rebuilt static archive

Depends-on: Rust compression and decompression streaming ABI ports

lib/deprecated/zbuff_common.c

@@ -1,26 +1 @@
-/*
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- * All rights reserved.
- *
- * This source code is licensed under both the BSD-style license (found in the
- * LICENSE file in the root directory of this source tree) and the GPLv2 (found
- * in the COPYING file in the root directory of this source tree).
- * You may select, at your option, one of the above-listed licenses.
- */
-
-/*-*************************************
-*  Dependencies
-***************************************/
-#include "../common/error_private.h"
-#include "zbuff.h"
-
-/*-****************************************
-*  ZBUFF Error Management  (deprecated)
-******************************************/
-
-/*! ZBUFF_isError() :
-*   tells if a return value is an error code */
-unsigned ZBUFF_isError(size_t errorCode) { return ERR_isError(errorCode); }
-/*! ZBUFF_getErrorName() :
-*   provides error code string from function result (useful for debugging) */
-const char* ZBUFF_getErrorName(size_t errorCode) { return ERR_getErrorName(errorCode); }
+/* ZBUFF compatibility symbols are implemented by rust/src/zbuff.rs. */