!136 merge cocreate-issue-url-gitcode into release/v4.23.1
[共创大赛] 支持 GitCode 镜像域名 Issue URL
Created-by: Graychao
Commit-by: Codex
Merged-by: saulcy
Description: ## Summary
- allow IssueRef::parse to accept gitcode.com issue URLs in addition to atomgit.com
- strip an optional host port before mirror-host validation
- add regression coverage for GitCode issue links and host-port issue URLs
## Why
parse_repo_url already treats gitcode.com as an AtomGit mirror, so a checkout whose origin is gitcode.com can be detected correctly. IssueRef::parse still rejected issue URLs copied from GitCode, which blocks /fixissue and related workflows for users who copy the issue link from the current GitCode UI.
## Verification
- docker run --rm -v /tmp/atomcode-cocreate-pr:/work -v /tmp/atomcode-cargo-registry:/usr/local/cargo/registry -w /work rust:1.88 cargo test -p atomcode-core --lib atomgit::url
- git diff --check
Note: a broader cargo test -p atomcode-core on current main is blocked by the existing hooks_integration test initializer missing plugin_root; this is covered separately by MR !134.
See merge request: atomgit_atomcode/atomcode!136