fix(clip): a clip refusal speaks the user's language, and a choice in the clip form no longer sends it

The backend refuses a clip with a structured reason, but the client showed every one as the generic
"couldn't make the clip": each reason now has its own message in both languages, held to the
backend's reasons in both directions by the contract test. A segmented toggle's and the priority
stepper's buttons had no type, so inside a form one of them submitted it.

frontend/src/i18n/locales/en/clip.json

@@ -17,5 +17,15 @@
   "cut": "Cut clip",
   "queued": "The clip is being made — it will be in your downloads",
   "view": "Downloads",
-  "failed": "Couldn’t make the clip"
+  "failed": "Couldn’t make the clip",
+  "errors": {
+    "bad_source": "This video can’t be clipped.",
+    "bad_range": "The clip’s start or end isn’t valid.",
+    "too_short": "A clip is at least a second long.",
+    "too_long": "A clip is at most 10 minutes long.",
+    "bad_audio": "That audio track isn’t available.",
+    "not_found": "This item is no longer in the library.",
+    "media_missing": "The item’s file can’t be reached from here.",
+    "past_end": "The clip runs past the end of the video."
+  }
 }

frontend/src/i18n/locales/hu/clip.json

@@ -17,5 +17,15 @@
   "cut": "Klip vágása",
   "queued": "Készül a klip — a letöltéseid közé kerül",
   "view": "Letöltések",
-  "failed": "Nem sikerült elkészíteni a klipet"
+  "failed": "Nem sikerült elkészíteni a klipet",
+  "errors": {
+    "bad_source": "Ebből a videóból nem lehet klipet vágni.",
+    "bad_range": "A klip eleje vagy vége érvénytelen.",
+    "too_short": "A klip legalább egy másodperc.",
+    "too_long": "A klip legfeljebb 10 perc lehet.",
+    "bad_audio": "Ez a hangsáv nem érhető el.",
+    "not_found": "Ez az elem már nincs a könyvtárban.",
+    "media_missing": "Az elem fájlja innen nem érhető el.",
+    "past_end": "A klip túlnyúlik a videó végén."
+  }
 }