release(broker): 0.9.1 — dependency refresh

[mack42]

Broker-only patch release: ramqp-broker 0.9.0 → 0.9.1. ramqp (0.8.2) and ramqp-core (0.2.5) are unchanged and are not re-published (release.yml skips already-published versions).

Changes

• Raised broker dependency minimums: openraft 0.9.25, serde 1.0.229, serde_json 1.0.151
• Regenerated Cargo.lock (tokio 1.53.1, futures 0.3.33, thiserror 2.0.19, and other patch updates) — this ships inside the broker package, so cargo install ramqp-broker --locked builds the daemon against these versions
• CHANGELOG entry + README crate-status table refresh (was stale at 0.8.1/0.2.4/"ships with the next tag")
• No code or API changes

Verification

• cargo test --all-features — all suites pass, 0 failures
• cargo clippy --all-targets --all-features -- -D warnings — clean
• cargo publish -p ramqp-broker --dry-run — packages and compiles against registry ramqp-core 0.2.5

After merge

Tag the merge commit v0.9.1-broker and push the tag — release.yml will test, skip core/client as already published, publish ramqp-broker 0.9.1, and cut the GitHub release.