feat(compress): move window clearing leaf into Rust

Keep the private ZSTD_window_t layout and pointer-difference calculation in C,
then route the size_t-to-U32 conversion and paired limit writes through a small
Rust ABI leaf. This removes the inline C window-clear implementation while
preserving its overflow behavior at both single-threaded and multithreaded
call sites.

Test Plan:
- cargo test --manifest-path rust/Cargo.toml --lib zstd_compress::tests (77 passed)
- make -C programs -j2 zstd
- rustfmt +nightly --edition 2021 rust/src/zstd_compress.rs --check
- make -C tests -j2 test-cli-tests (41 passed)
- make -C tests -j2 test-legacy test-invalidDictionaries test-decodecorpus test-rust-lib-smoke (passed)
- git diff --check

lib/compress/zstd_compress.c

@@ -1486,7 +1486,8 @@ void ZSTD_reset_compressedBlockState(ZSTD_compressedBlockState_t* bs)
  */
 static void ZSTD_invalidateMatchState(ZSTD_MatchState_t* ms)
 {
-    ZSTD_window_clear(&ms->window);
+    ZSTD_rust_windowClear((size_t)(ms->window.nextSrc - ms->window.base),
+                          &ms->window.lowLimit, &ms->window.dictLimit);
 
     ms->nextToUpdate = ms->window.dictLimit;
     ms->loadedDictEnd = 0;
@@ -1893,7 +1894,11 @@ ZSTD_resetCCtx_byAttachingCDict(ZSTD_CCtx* cctx,
             if (cctx->blockState.matchState.window.dictLimit < cdictEnd) {
                 cctx->blockState.matchState.window.nextSrc =
                     cctx->blockState.matchState.window.base + cdictEnd;
-                ZSTD_window_clear(&cctx->blockState.matchState.window);
+                ZSTD_rust_windowClear(
+                    (size_t)(cctx->blockState.matchState.window.nextSrc -
+                             cctx->blockState.matchState.window.base),
+                    &cctx->blockState.matchState.window.lowLimit,
+                    &cctx->blockState.matchState.window.dictLimit);
             }
             /* loadedDictEnd is expressed within the referential of the active context */
             cctx->blockState.matchState.loadedDictEnd = cctx->blockState.matchState.window.dictLimit;