refactor: drop dead code and use the standard library where it already does the job (#76)

No behaviour change.

- Deleted, unused or one-line wrappers: panes.RuneIndexes, Detail.Refresh (SetDescribed does it), SecretValue.Len, Query.Empty, Clipboard.Native, config.Load, get's value, Model.done, providerOf (cachefile.ProviderOf), contextWithTimeout, searchCoverage, startCrawl, showKeybindings, the expiry aliases and daysLeft.
- cmp.Or instead of the two cmpOr copies; slices.Sorted(maps.Keys(…)), maps.Copy, wg.Go, utf8.RuneCountInString and new(true) instead of loops and helpers that do the same.
- A container's pane title is set once, not twice; a redundant length check in share links and a no-op assignment in linkhandler.Launch are gone.
- Tests call ansi.Strip and lastLines directly; gofmt -s on links.go.

Reviewed-on: #76
Co-authored-by: Karl-Einar Bergstrøm <karl-einarb@outlook.com>

internal/ui/keys/keys.go

@@ -15,8 +15,8 @@ package keys
 
 import (
 	"fmt"
+	"maps"
 	"slices"
-	"sort"
 	"strings"
 
 	"charm.land/bubbles/v2/key"
@@ -266,11 +266,11 @@ func (m *Map) Apply(cfg map[string]map[string][]string) error {
 		byName[a.Context+"."+a.Name] = a
 		contexts[a.Context] = true
 	}
-	for _, ctx := range sortedKeys(cfg) {
+	for _, ctx := range slices.Sorted(maps.Keys(cfg)) {
 		if !contexts[ctx] {
-			return fmt.Errorf("keybinding: unknown context %q (known: %s)", ctx, strings.Join(sortedKeys(contexts), ", "))
+			return fmt.Errorf("keybinding: unknown context %q (known: %s)", ctx, strings.Join(slices.Sorted(maps.Keys(contexts)), ", "))
 		}
-		for _, name := range sortedKeys(cfg[ctx]) {
+		for _, name := range slices.Sorted(maps.Keys(cfg[ctx])) {
 			a, ok := byName[ctx+"."+name]
 			if !ok {
 				return fmt.Errorf("keybinding.%s: unknown action %q (known: %s)", ctx, name, strings.Join(m.names(ctx), ", "))
@@ -289,16 +289,7 @@ func (m *Map) names(ctx string) []string {
 			out = append(out, a.Name)
 		}
 	}
-	sort.Strings(out)
-	return out
-}
-
-func sortedKeys[V any](set map[string]V) []string {
-	out := make([]string, 0, len(set))
-	for k := range set {
-		out = append(out, k)
-	}
-	sort.Strings(out)
+	slices.Sort(out)
 	return out
 }