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>

services/context/pagination.go

@@ -6,6 +6,7 @@ package context
 import (
 	"fmt"
 	"html/template"
+	"math"
 	"net/http"
 	"net/url"
 	"slices"
@@ -22,11 +23,13 @@ type Pagination struct {
 }
 
 // NewPagination creates a new instance of the Pagination struct.
+// "total" is usually from database result "count int64", so it also uses int64
 // "pagingNum" is "page size" or "limit", "current" is "page"
 // total=-1 means only showing prev/next
-func NewPagination(total, pagingNum, current, numPages int) *Pagination {
+func NewPagination(total int64, pagingNum, current, numPages int) *Pagination {
+	totalInt := int(min(total, int64(math.MaxInt)))
 	p := &Pagination{}
-	p.Paginater = paginator.New(total, pagingNum, current, numPages)
+	p.Paginater = paginator.New(totalInt, pagingNum, current, numPages)
 	return p
 }