feat(keys): paste-your-key field — snippets carry the real key instantly

Next to the copy button: a key input and an «Insert key» button (Enter works
too). The pasted key substitutes into every harness/SDK snippet immediately
and survives tab and OS switches; a freshly created key pre-fills the field.
No more copying a snippet and then hand-editing the placeholder. 2 strings
×7 languages.

web/js/i18n/tr.js

@@ -644,4 +644,6 @@ export default {
   "keys.budgetOf": "bütçe {b}/ay",
   "dash.kpi.orBalance": "OpenRouter bakiyesi",
   "keys.h.install": "Kurulum:",
+  "keys.snip.keyInputPh": "API anahtarınızı yapıştırın",
+  "keys.snip.apply": "Anahtarı ekle",
 };