Clarify reserved async feature docs

Author: eldryoth

CHANGELOG.md

@@ -35,6 +35,8 @@
   feature-bundle check so NEON reserved-build evidence runs in automation.
 - Hardened release metadata validation to require the published crate package
   to include the SIMD admission policy and unsafe inventory documents.
+- Clarified 0.5 development documentation around benchmark claims and reserved
+  `tokio` feature behavior.
 - Updated security documentation for streaming wrapper buffer cleanup behavior.
 - Updated release evidence documentation for stream fuzzing and reserved SIMD
   feature-bundle checks.

README.md

@@ -58,8 +58,8 @@ license = "MIT OR Apache-2.0"
 | `std` | yes | `std::error::Error` support and feature base for I/O. |
 | `simd` | no | Future hardware acceleration. |
 | `stream` | no | `std::io` streaming wrappers. |
-| `tokio` | no | Future async streaming wrappers. |
-| `kani` | no | Future verifier harnesses. |
+| `tokio` | no | Reserved for future async streaming wrappers; currently adds no dependencies or APIs. |
+| `kani` | no | Reserved for verifier harnesses; normal builds do not require Kani. |
 | `fuzzing` | no | Reserved for verifier and fuzz harness integration; published crate stays dependency-free. |
 
 Disable defaults for embedded or freestanding use:

docs/BENCHMARKS.md

@@ -38,7 +38,7 @@ decode lookup table. That keeps the default implementation aligned with the
 side-channel hardening roadmap, but it is expected to trail highly optimized
 table-based decoders on large buffers.
 
-Treat scalar decode throughput as an optimization target for `0.4.1`, not as a
-release claim. Any future fast scalar or SIMD path must preserve strict error
-indexes, canonical padding rejection, Miri cleanliness, and scalar/SIMD
-differential test evidence.
+Treat scalar decode throughput as an optimization target for the current
+development cycle, not as a release claim. Any future fast scalar or SIMD path
+must preserve strict error indexes, canonical padding rejection, Miri
+cleanliness, and scalar/SIMD differential test evidence.

docs/MIGRATION.md

@@ -166,7 +166,8 @@ let encoded = encoder.finish().unwrap();
 assert_eq!(encoded, b"aGVsbG8=");
 ```
 
-Tokio wrappers are planned but are not part of `0.4.1`.
+The `tokio` feature is reserved for future async wrappers. It currently adds
+no dependencies or APIs.
 
 ## Security Notes
 

docs/PLAN.md

@@ -81,8 +81,8 @@ Any dependency addition must answer:
    - Chunk-boundary state machines.
 
 5. `tokio`
-   - Future async wrappers.
-   - Explicit optional dependency.
+   - Reserved feature for future async wrappers.
+   - Explicit optional dependency only if the async API is admitted.
 
 ### API Policy