feat(io): make bytes optional

[George-Miao]

No description provided.

[Copilot]

Pull request overview

This PR makes the bytes integration in compio-io feature-gated so consumers can build without pulling in bytes via compio-buf, while keeping the previous behavior enabled by default.

Changes:

• Gate framed::codec::bytes and BytesFramed behind a new bytes feature (enabled by default).
• Update compio-io’s dependency on compio-buf to no longer always enable its bytes feature.
• Replace bytes-trait-based length encoding/decoding in LengthDelimited with a std::io::Write-based approach.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 8 comments.

File	Description
compio-io/src/framed/mod.rs	Adds a BytesFramed alias behind feature = "bytes" and updates docs/imports accordingly.
compio-io/src/framed/frame.rs	Reworks LengthDelimited header encoding/decoding to avoid bytes traits.
compio-io/src/framed/codec/mod.rs	Gates the bytes codec module behind feature = "bytes".
compio-io/Cargo.toml	Removes unconditional compio-buf/bytes dependency feature and introduces a bytes feature (default-on).

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[George-Miao]

Just to clarify on the panicking: By default bytes' Buf and BufMut's non-try_ methods will also panic in case of overly large LFL. This change just makes it panic during initialization instead of runtime.

[Berrysoft]

LGTM