fix(git/hook): make sync_tags Send-safe by collecting git2 data synchronously

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.

libs/git/hook/sync/commit.rs

@@ -22,8 +22,7 @@ pub(crate) struct BranchTip {
 }
 
 /// Owned tag data collected from git2 (no git2 types after this).
-/// Used by sync_tags; currently populated by collect_git_refs but not yet consumed.
-#[allow(dead_code)]
+/// Consumed by sync_tags via collect_tag_refs().
 #[derive(Debug, Clone)]
 pub(crate) struct TagTip {
     pub name: String,

libs/git/hook/sync/tag.rs

@@ -1,3 +1,4 @@
+use crate::hook::sync::commit::TagTip;
 use crate::GitError;
 use crate::hook::sync::HookMetaDataSync;
 use db::database::AppTransaction;
@@ -7,21 +8,15 @@ use sea_orm::*;
 use std::collections::HashSet;
 
 impl HookMetaDataSync {
-    pub async fn sync_tags(&self, txn: &AppTransaction) -> Result<(), GitError> {
-        let repo_id = self.repo.id;
+    /// Collect all tag metadata from git2 into owned structs.
+    /// This is sync and must be called from a `spawn_blocking` context.
+    pub(crate) fn collect_tag_refs(&self) -> Result<Vec<TagTip>, GitError> {
         let repo = self.domain.repo();
-
-        let existing: Vec<repo_tag::Model> = repo_tag::Entity::find()
-            .filter(repo_tag::Column::Repo.eq(repo_id))
-            .all(txn)
-            .await
-            .map_err(|e| GitError::IoError(format!("failed to query tags: {}", e)))?;
-        let mut existing_names: HashSet<String> = existing.iter().map(|t| t.name.clone()).collect();
-
         let tag_names = repo
             .tag_names(None)
             .map_err(|e| GitError::Internal(e.to_string()))?;
 
+        let mut tags = Vec::new();
         for tag_name in tag_names.iter().flatten() {
             let full_ref = format!("refs/tags/{}", tag_name);
             let reference = match repo.find_reference(&full_ref) {
@@ -53,28 +48,53 @@ impl HookMetaDataSync {
                 (None, String::new(), String::new())
             };
 
-            if existing_names.contains(tag_name) {
-                existing_names.remove(tag_name);
+            tags.push(TagTip {
+                name: tag_name.to_string(),
+                target_oid,
+                description,
+                tagger_name,
+                tagger_email,
+            });
+        }
+
+        Ok(tags)
+    }
+
+    pub async fn sync_tags(&self, txn: &AppTransaction) -> Result<(), GitError> {
+        let repo_id = self.repo.id;
+
+        let existing: Vec<repo_tag::Model> = repo_tag::Entity::find()
+            .filter(repo_tag::Column::Repo.eq(repo_id))
+            .all(txn)
+            .await
+            .map_err(|e| GitError::IoError(format!("failed to query tags: {}", e)))?;
+        let mut existing_names: HashSet<String> = existing.iter().map(|t| t.name.clone()).collect();
+
+        let tags = self.collect_tag_refs()?;
+
+        for tag in tags {
+            if existing_names.contains(&tag.name) {
+                existing_names.remove(&tag.name);
                 repo_tag::Entity::update_many()
                     .filter(repo_tag::Column::Repo.eq(repo_id))
-                    .filter(repo_tag::Column::Name.eq(tag_name))
-                    .col_expr(repo_tag::Column::Oid, Expr::value(&target_oid))
-                    .col_expr(repo_tag::Column::Description, Expr::value(description))
-                    .col_expr(repo_tag::Column::TaggerName, Expr::value(&tagger_name))
-                    .col_expr(repo_tag::Column::TaggerEmail, Expr::value(&tagger_email))
+                    .filter(repo_tag::Column::Name.eq(&tag.name))
+                    .col_expr(repo_tag::Column::Oid, Expr::value(&tag.target_oid))
+                    .col_expr(repo_tag::Column::Description, Expr::value(tag.description.clone()))
+                    .col_expr(repo_tag::Column::TaggerName, Expr::value(&tag.tagger_name))
+                    .col_expr(repo_tag::Column::TaggerEmail, Expr::value(&tag.tagger_email))
                     .exec(txn)
                     .await
                     .map_err(|e| GitError::IoError(format!("failed to update tag: {}", e)))?;
             } else {
                 let new_tag = repo_tag::ActiveModel {
                     repo: Set(repo_id),
-                    name: Set(tag_name.to_string()),
-                    oid: Set(target_oid),
+                    name: Set(tag.name.clone()),
+                    oid: Set(tag.target_oid),
                     color: Set(None),
-                    description: Set(description),
+                    description: Set(tag.description.clone()),
                     created_at: Set(chrono::Utc::now()),
-                    tagger_name: Set(tagger_name),
-                    tagger_email: Set(tagger_email),
+                    tagger_name: Set(tag.tagger_name.clone()),
+                    tagger_email: Set(tag.tagger_email.clone()),
                     tagger: Set(None),
                     ..Default::default()
                 };