refactor: reuse the existing service and rendering helpers

services.IsNotFound replaces the hand-rolled 404 checks, convertPage
the copied page conversions and lastPathNumber the comment's own
number parser. The List wrappers around ListPage of releases,
branches, wiki pages, secrets and variables go, pull request filters
resolve milestones through Milestones.FindOne like issues, and
localFlagsChanged, boolOrder, Cell.Render, stateBadge and dueText
replace their copies.

Signed-off-by: bircni <bircni@icloud.com>

internal/app/issues.go

@@ -8,7 +8,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"net/http"
 	"net/url"
 	"path/filepath"
 	"strconv"
@@ -18,7 +17,6 @@ import (
 	"gitea.dev/tea/internal/clierr"
 	"gitea.dev/tea/internal/services"
 	"gitea.dev/tea/internal/terminal"
-	"gitea.dev/tea/internal/transport"
 	"github.com/spf13/cobra"
 )
 
@@ -490,7 +488,7 @@ func issueLabel(n int64) string { return fmt.Sprintf("issue %d", n) }
 // itemError words the failure of one item of a batch, which the batch prefixes with the item, such
 // as "issue 9: not found in alice/x".
 func itemError(err error, scope string) error {
-	if apiErr, ok := errors.AsType[*transport.APIError](err); ok && apiErr.Status == http.StatusNotFound {
+	if services.IsNotFound(err) {
 		return explain(err, "not found in %s", scope)
 	}
 	return err