Fix CodeQL code scanning alerts (#36858)

Fixes 10 CodeQL code scanning alerts:

- Change `NewPagination`/`SetLinkHeader` to accept `int64` for total
count, clamping internally to fix incorrect-integer-conversion alerts
([#110](https://github.com/go-gitea/gitea/security/code-scanning/110),
[#114](https://github.com/go-gitea/gitea/security/code-scanning/114),
[#115](https://github.com/go-gitea/gitea/security/code-scanning/115),
[#116](https://github.com/go-gitea/gitea/security/code-scanning/116))
- Use `strconv.Atoi()` in `htmlrenderer.go` to avoid int64 intermediate
([#105](https://github.com/go-gitea/gitea/security/code-scanning/105),
[#106](https://github.com/go-gitea/gitea/security/code-scanning/106))
- Clamp regex match indices in `escape_stream.go` to fix
allocation-size-overflow
([#161](https://github.com/go-gitea/gitea/security/code-scanning/161),
[#162](https://github.com/go-gitea/gitea/security/code-scanning/162),
[#163](https://github.com/go-gitea/gitea/security/code-scanning/163))
- Cap slice pre-allocation in `GetIssueDependencies`
([#181](https://github.com/go-gitea/gitea/security/code-scanning/181))

---------

Co-authored-by: Claude (Opus 4.6) <noreply@anthropic.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/web/repo/projects.go

@@ -66,13 +66,6 @@ func Projects(ctx *context.Context) {
 	ctx.Data["OpenCount"] = repo.NumOpenProjects
 	ctx.Data["ClosedCount"] = repo.NumClosedProjects
 
-	var total int
-	if !isShowClosed {
-		total = repo.NumOpenProjects
-	} else {
-		total = repo.NumClosedProjects
-	}
-
 	projects, count, err := db.FindAndCount[project_model.Project](ctx, project_model.SearchOptions{
 		ListOptions: db.ListOptions{
 			PageSize: setting.UI.IssuePagingNum,
@@ -111,12 +104,7 @@ func Projects(ctx *context.Context) {
 		ctx.Data["State"] = "open"
 	}
 
-	numPages := 0
-	if count > 0 {
-		numPages = (int(count) - 1/setting.UI.IssuePagingNum)
-	}
-
-	pager := context.NewPagination(total, setting.UI.IssuePagingNum, page, numPages)
+	pager := context.NewPagination(count, setting.UI.IssuePagingNum, page, 5)
 	pager.AddParamFromRequest(ctx.Req)
 	ctx.Data["Page"] = pager