deps: zig-libp2p v0.2.89

[zclawz]

Updates zig_libp2p from v0.2.87 to v0.2.89 in build.zig.zon.

[zclawz]

This is blocking the devnet5 v0.5.7 release. The failed run https://github.com/blockblaz/zeam/actions/runs/29189439103 died in create-tags because the repo only allows squash merges, so the release PR head SHA is not reachable from main. This PR falls back to github.event.pull_request.merge_commit_sha for squash-merged release PRs. After this is approved/merged, recreate the release branch from updated main with labels release, devnet5, 0.5.7 to produce the missing v0.5.7/devnet5 artifacts.

[zclawz]

Closing this: I misread the request as needing a workflow fix. The documented RELEASE.md path is to recreate release from origin/main with an empty release commit and labels. I opened #1034 for that release instead.

[zclawz]

Updated this PR with deps: zig-libp2p v0.2.88 in commit 735a9142. I validated the new Zig package hash with zig build --fetch --summary none.

[zclawz]

Reset this PR branch to contain only the zig-libp2p v0.2.88 dependency bump on top of origin/main. New head: 4695d67a.

[zclawz]

Pushed 52556b0e to pin zig_libp2p v0.2.88 to the immutable release commit archive. Clean zig fetch against commit 39f9200d93a32721f6a90cd7039e765337aed714 returns zig_libp2p-0.2.88-lil2hIVfKgDorvERqyGdLKRe4SsC4Z9eCSMU9gIppynH. The refs/tags/v0.2.88 archive currently 404s upstream because the tag was superseded.

[zclawz]

Squashed the PR branch to one clean dependency-bump commit: 290fb3b3. It uses the immutable v0.2.88 release commit archive and the clean-fetch hash zig_libp2p-0.2.88-lil2hIVfKgDorvERqyGdLKRe4SsC4Z9eCSMU9gIppynH.

[zclawz]

Corrected to v0.2.89 and force-pushed a clean single-commit PR branch: aac80159. Clean zig fetch for refs/tags/v0.2.89 returned zig_libp2p-0.2.89-lil2hMltKgA7YdmHAS_eavWH0unkgsQhybBFEWqukws4.

[zclawz]

Closing this PR per request; the dependency bump will be applied to PR #1030 instead.