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/repository/adopt.go

@@ -240,16 +240,15 @@ func DeleteUnadoptedRepository(ctx context.Context, doer, u *user_model.User, re
 
 type unadoptedRepositories struct {
 	repositories []string
-	index        int
-	start        int
-	end          int
+	count        int64
+	start, end   int64
 }
 
 func (unadopted *unadoptedRepositories) add(repository string) {
-	if unadopted.index >= unadopted.start && unadopted.index < unadopted.end {
+	if unadopted.count >= unadopted.start && unadopted.count < unadopted.end {
 		unadopted.repositories = append(unadopted.repositories, repository)
 	}
-	unadopted.index++
+	unadopted.count++
 }
 
 func checkUnadoptedRepositories(ctx context.Context, userName string, repoNamesToCheck []string, unadopted *unadoptedRepositories) error {
@@ -291,7 +290,7 @@ func checkUnadoptedRepositories(ctx context.Context, userName string, repoNamesT
 }
 
 // ListUnadoptedRepositories lists all the unadopted repositories that match the provided query
-func ListUnadoptedRepositories(ctx context.Context, query string, opts *db.ListOptions) ([]string, int, error) {
+func ListUnadoptedRepositories(ctx context.Context, query string, opts *db.ListOptions) ([]string, int64, error) {
 	globUser, _ := glob.Compile("*")
 	globRepo, _ := glob.Compile("*")
 
@@ -311,12 +310,12 @@ func ListUnadoptedRepositories(ctx context.Context, query string, opts *db.ListO
 	}
 	var repoNamesToCheck []string
 
-	start := (opts.Page - 1) * opts.PageSize
+	start := int64((opts.Page - 1) * opts.PageSize)
 	unadopted := &unadoptedRepositories{
 		repositories: make([]string, 0, opts.PageSize),
 		start:        start,
-		end:          start + opts.PageSize,
-		index:        0,
+		end:          start + int64(opts.PageSize),
+		count:        0,
 	}
 
 	var userName string
@@ -372,5 +371,5 @@ func ListUnadoptedRepositories(ctx context.Context, query string, opts *db.ListO
 		return nil, 0, err
 	}
 
-	return unadopted.repositories, unadopted.index, nil
+	return unadopted.repositories, unadopted.count, nil
 }