refactor(compress): expose compressed block reset from Rust

The compressed-block reset logic was already implemented in Rust, but the
Rust export used a private bridge name and C retained a forwarding wrapper
under the original ABI name. Export the original
`ZSTD_reset_compressedBlockState` symbol directly from Rust, keep the
`ZSTD_rust_resetCompressedBlockState` crate-local alias for existing Rust
callers, and remove only the redundant C declaration and body. Private
context-layout code and other C functions remain unchanged.

Test Plan:
- `git diff --check` -- passed.
- `cc -std=c99 -Ilib -Ilib/common -Ilib/compress -Ilib/decompress -Ilib/dict -fsyntax-only lib/compress/zstd_compress.c` -- passed.
- `cargo +nightly fmt --manifest-path rust/Cargo.toml --all -- --check` -- passed.
- Cargo build/test and make were intentionally not run per the requested lightweight-only scope.

rust/src/zstd_compress_stats.rs

@@ -1089,7 +1089,7 @@ pub unsafe extern "C" fn ZSTD_rust_postProcessSequenceProducerResult(
 /// `ZSTD_reset_compressedBlockState()`.  The caller must provide a valid
 /// mutable compressed block state.
 #[no_mangle]
-pub unsafe extern "C" fn ZSTD_rust_resetCompressedBlockState(
+pub unsafe extern "C" fn ZSTD_reset_compressedBlockState(
     block_state: *mut ZSTD_compressedBlockState_t,
 ) {
     let block_state = unsafe { &mut *block_state };
@@ -1100,6 +1100,8 @@ pub unsafe extern "C" fn ZSTD_rust_resetCompressedBlockState(
     block_state.entropy.fse.litlength_repeatMode = FSE_REPEAT_NONE;
 }
 
+pub(crate) use ZSTD_reset_compressedBlockState as ZSTD_rust_resetCompressedBlockState;
+
 /// Swaps the two C-owned block-state pointers after a block is confirmed.
 ///
 /// The enclosing `ZSTD_blockState_t` contains C-only match-state storage, so
@@ -3287,7 +3289,7 @@ mod tests {
         block_state.entropy.fse.matchlength_repeatMode = 1;
         block_state.entropy.fse.litlength_repeatMode = 2;
 
-        unsafe { ZSTD_rust_resetCompressedBlockState(&mut block_state) };
+        unsafe { ZSTD_reset_compressedBlockState(&mut block_state) };
 
         assert_eq!(block_state.rep, [1, 4, 8]);
         assert_eq!(block_state.entropy.huf.repeatMode, HUF_REPEAT_NONE);