refactor: replace sort.Strings with slices.Sort (#23457)

The slices package provides type-safe generic replacements for the
old typed sort convenience functions. The codebase already uses
slices.Sort in 43 call sites; this finishes the migration for the
remaining 29.

- sort.Strings(x)          -> slices.Sort(x)
- sort.Float64s(x)         -> slices.Sort(x)
- sort.StringsAreSorted(x) -> slices.IsSorted(x)

agent/agentgit/pathstore.go

@@ -1,7 +1,7 @@
 package agentgit
 
 import (
-	"sort"
+	"slices"
 	"sync"
 
 	"github.com/google/uuid"
@@ -99,7 +99,7 @@ func (ps *PathStore) GetPaths(chatID uuid.UUID) []string {
 	for p := range m {
 		out = append(out, p)
 	}
-	sort.Strings(out)
+	slices.Sort(out)
 	return out
 }