Fix bincode dependency: revert to 2.0.0-rc.3 and remove derive feature

[dependabot]

Fixes the build error introduced by updating bincode to 3.0.0. The bincode 3.0.0 package on crates.io is a protest/joke package that unconditionally emits a compile_error! and cannot be compiled. This PR reverts the bincode requirement back to 2.0.0-rc.3 (which resolves to the actual v2.0.1 release) and removes the unused derive feature flag.

Changes Made

• Version: Reverted bincode from 3.0.0 back to 2.0.0-rc.3 in both Cargo.toml and src/kete_core/Cargo.toml
• Features: Removed the derive feature (unused in the codebase); retained the serde feature required by bincode::serde::* APIs used throughout the code

Testing

• ✅ cargo check completes successfully, resolving to bincode v2.0.1

[annie444]

@copilot fix the build error (remove the derive feature from bincode)

[Copilot]

@copilot fix the build error (remove the derive feature from bincode)

Done in the latest commit. I also had to revert the version from 3.0.0 back to 2.0.0-rc.3 — bincode 3.0.0 on crates.io is a joke package that unconditionally emits a compile_error!, so it can't be used at all. With the version reverted and derive removed, cargo check now resolves to bincode v2.0.1 and builds cleanly.

[annie444]

@dependabot ignore this dependency

[dependabot]

OK, I won't notify you about bincode again, unless you re-open this PR.