sync_tags held git2 types (StringArray, Repository) across .await points
on sea-orm DB operations. Applied the same pattern as sync_refs:
- Added collect_tag_refs() sync helper that collects all tag metadata
(name, oid, description, tagger) into owned TagTip structs.
- sync_tags now calls collect_tag_refs() before any .await, so no git2
types cross the async boundary.
- Removed #[allow(dead_code)] from TagTip now that it's consumed.
- pool/worker.rs: only dispatch webhooks after sync succeeds (skip on error);
pass max_retries from PoolConfig to HookWorker
- sync/branch.rs: replaced with stub (sync_refs moved to commit.rs)
- sync/commit.rs: add collect_git_refs() that collects BranchTip/TagTip from
git2 entirely within one sync call; sync_refs now uses owned data so no
git2 types cross .await boundaries (future is Send)
- sync/fsck.rs: remove extraneous "HEAD" arg from rollback git update-ref
(correct syntax is: update-ref -m <msg> <ref> <new-sha> — no old-sha)
- webhook_dispatch.rs: touch_count uses Expr::col().add(1) for atomic
increment instead of overwriting with Expr::value(1)
- pool/mod.rs: pass config.redis_max_retries to HookWorker
