feat(compress): move match-state reset policy into Rust

Move the reset decision tree for match-state tables from C into a Rust-owned
callback projection. Rust now decides chain/hash3/row/optimal allocations,
reset versus continue behavior, clean versus leave-dirty policy, scalar
publication, and allocation-error propagation. C retains the cwksp phases,
window invalidation, private pointer assignments, zeroing, and hash-salt
implementation behind callbacks, so the private match-state and workspace
layouts remain C-owned.

Update the migration boundary documentation and add callback-order probes for
CCtx optimal storage, CCtx row salting, CDict row zeroing, and table allocation
failure.

Test Plan:
- cargo fmt --manifest-path rust/Cargo.toml -- --check
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo test --manifest-path rust/Cargo.toml --lib (677 passed)
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo clippy --manifest-path rust/Cargo.toml --all-targets -- -D warnings
- ulimit -v 41943040; make -B -C programs -j1 zstd
- ulimit -v 41943040; make -C tests -j1 test-zstream ZSTREAM_TESTTIME=-T1s (84 tests and both short fuzzer rounds)

rust/README.md

@@ -166,10 +166,10 @@ CDict advanced private workspace construction, private static-CCtx and
 static-CDict workspace construction and dictionary-content allocation/loading,
 and advanced-CDict dictionary-content loading remain in C. Rust now owns
 advanced-CDict custom-memory validation, workspace-size query/allocation,
-allocation/create/init cleanup ordering, and the CCtx workspace-size formula;
-C retains private layout-size inputs, workspace layout, and allocator
-callbacks. Reset policy,
-private CCtx/matchfinder/workspace operations, and codec/adaptive-policy
+allocation/create/init cleanup ordering, the CCtx workspace-size formula, and
+the match-state reset policy/order; C retains private layout-size inputs,
+workspace layout, and allocator callbacks. Private CCtx reset/matchfinder/
+workspace operations and codec/adaptive-policy
 callbacks remain in C. CDict initialization ordering and scalar publication,
 shared compression-begin dictionary selection, CDict reset attach-versus-copy
 selection, and CDict-begin parameter selection, initialization ordering, and