perf: speed up the issue and pull request dashboards and fix table indices (#40001) (#40096)

Backport #40001 by @silverwind

The dashboard counts ran queries whose cost grew with the whole instance
instead of the viewing user. On https://gitea.com/pulls the two review
counts alone take about 1.4s per page load.

- Check the owner of the already joined repository with `EXISTS` instead
of listing every public repository and public user
- Hide superseded review requests with `NOT EXISTS` instead of grouping
every review on the instance
- Skip the review counts on `/issues`, which never shows them
- Index `team_user.uid` for permission and team lookups by user
- Fix indices for table `watch`, `package_property` and `action_run`,
fix #40090

Median page times in ms, before → after, on a synthetic dataset sized
like gitea.com (175k users, 40k repos, 120k issues, 1M comments):

| Page | SQLite | PostgreSQL 17 | MySQL 8.4 | MariaDB 13 |
|---|---|---|---|---|
| `/pulls` | 901 → 56 | 330 → 156 | 189 → 124 | 192 → 218 |
| `/pulls?type=review_requested` | 1797 → 66 | 557 → 254 | 307 → 245 |
604 → 499 |
| `/pulls?type=reviewed_by` | 1646 → 118 | 537 → 316 | 515 → 265 | 528 →
682 |
| `/pulls?type=mentioned` | 1403 → 46 | 426 → 119 | 165 → 116 | 179 →
179 |
| `/issues` | 923 → 33 | 293 → 39 | 178 → 65 | 140 → 41 |
| `/api/v1/repos/issues/search` (anonymous) | 870 → 110 | 144 → 104 |
123 → 87 | 170 → 193 |

MariaDB checks the owner per row on long scans across all public
repositories, which makes a few pages slower there.

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/issues/issue_search.go

@@ -218,10 +218,7 @@ func applyRepoConditions(sess db.Session, opts *IssuesOptions) {
 		opts.RepoCond = builder.In("issue.repo_id", opts.RepoIDs)
 	}
 	if opts.AllPublic {
-		if opts.RepoCond == nil {
-			opts.RepoCond = builder.NewCond()
-		}
-		opts.RepoCond = opts.RepoCond.Or(builder.In("issue.repo_id", builder.Select("id").From("repository").Where(repo_model.PublicRepoUnderPublicOwnerCond())))
+		opts.RepoCond = builder.Or(opts.RepoCond, repo_model.PublicRepoUnderPublicOwnerCond())
 	}
 	if opts.RepoCond != nil {
 		sess.And(opts.RepoCond)
@@ -402,22 +399,17 @@ func applyReviewRequestedCondition(sess db.Session, reviewRequestedID int64) {
 		From("team_user").
 		Where(builder.Eq{"team_user.uid": reviewRequestedID})
 
-	// if the review is approved or rejected, it should not be shown in the review requested list
-	maxReview := builder.Select("MAX(r.id)").
-		From("review as r").
-		Where(builder.In("r.type", []ReviewType{ReviewTypeApprove, ReviewTypeReject, ReviewTypeRequest})).
-		GroupBy("r.issue_id, r.reviewer_id, r.reviewer_team_id")
-
 	subQuery := builder.Select("review.issue_id").
 		From("review").
-		Where(builder.And(
-			builder.Eq{"review.type": ReviewTypeRequest},
-			builder.Or(
-				builder.Eq{"review.reviewer_id": reviewRequestedID},
-				builder.In("review.reviewer_team_id", existInTeamQuery),
-			),
-			builder.In("review.id", maxReview),
-		))
+		Where(builder.Eq{"review.type": ReviewTypeRequest}).
+		And(builder.Or(
+			builder.Eq{"review.reviewer_id": reviewRequestedID},
+			builder.In("review.reviewer_team_id", existInTeamQuery),
+		)).
+		// if the review is approved or rejected, it should not be shown in the review requested list
+		And(builder.NotExists(builder.Select("1").From("review as r").
+			Where(builder.Expr("r.issue_id = review.issue_id AND r.reviewer_id = review.reviewer_id AND r.reviewer_team_id = review.reviewer_team_id AND r.id > review.id").
+				And(builder.In("r.type", []ReviewType{ReviewTypeApprove, ReviewTypeReject, ReviewTypeRequest})))))
 	sess.Where("issue.poster_id <> ?", reviewRequestedID).
 		And(builder.In("issue.id", subQuery))
 }