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/release.go

@@ -187,7 +187,7 @@ func Releases(ctx *context.Context) {
 	ctx.Data["Releases"] = releases
 
 	numReleases := ctx.Data["NumReleases"].(int64)
-	pager := context.NewPagination(int(numReleases), listOptions.PageSize, listOptions.Page, 5)
+	pager := context.NewPagination(numReleases, listOptions.PageSize, listOptions.Page, 5)
 	pager.AddParamFromRequest(ctx.Req)
 	ctx.Data["Page"] = pager
 	ctx.HTML(http.StatusOK, tplReleasesList)
@@ -239,7 +239,7 @@ func TagsList(ctx *context.Context) {
 	ctx.Data["Releases"] = releases
 	ctx.Data["TagCount"] = count
 
-	pager := context.NewPagination(int(count), opts.PageSize, opts.Page, 5)
+	pager := context.NewPagination(count, opts.PageSize, opts.Page, 5)
 	pager.AddParamFromRequest(ctx.Req)
 	ctx.Data["Page"] = pager
 	ctx.Data["PageIsViewCode"] = !ctx.Repo.Repository.UnitEnabled(ctx, unit.TypeReleases)