Move the post-split partition loop out of zstd_compress.c while keeping the
private CCtx, matchfinder sequence-store construction, and split discovery in
C. Rust now receives a layout-asserted projection containing sequence-store
views, block-state slots, workspace and scalar policy, then mirrors the C
loop's dRep/cRep histories, final-literal accounting, repeated single-block
serialization, and final dRep publication.
Remove the obsolete C sequence-store/count/chunk wrappers and the debug-only
C size-estimation path that was coupled to the old loop. Add a focused Rust
fixture covering partition payloads and final literals, and document the new
ownership boundary for the split search and emission paths.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --lib -- --test-threads=1 (448 passed)
- cargo clippy --manifest-path rust/Cargo.toml --lib -- -D warnings (passed)
- cargo clippy --manifest-path rust/Cargo.toml -- -D warnings (passed)
- cargo +nightly fmt --manifest-path rust/Cargo.toml -- --check (passed)
- cargo clippy --tests/--benches remain blocked only by the pre-existing manual_repeat_n lint in one_shot_promotes_nonfirst_rle_blocks
- make -B -C lib -j2 lib (passed)
- make -B -C tests -j2 test-zstd (passed)
- make -B -C tests -j2 test-cli-tests (41 passed)
- ZSTREAM_TESTTIME=-T2s make -B -C tests -j2 test-zstream (passed)
- FUZZERTEST=-T5s make -B -C tests -j2 test-fuzzer (252 passed)
- make -B -C tests/fuzz -j2 all and sequence_compression_api (passed)