feat(playback): recommend recovery actions (#1374)

* docs(playback): design recovery recommendations

* docs(playback): plan recovery recommendations

* refactor(playback): extract diagnostic utilities

* feat(playback): define recovery recommendation contracts

* feat(playback): rank recovery recommendations

* feat(playback): track session recovery attempts

* feat(playback): identify content recovery sessions

* feat(ui): add ranked playback diagnostic panel

* feat(playback): switch temporarily to recommended players

* test(playback): cover temporary player recommendation

* test(playback): verify recommendation capability guards

* docs(playback): document recovery recommendations

* fix(playback): keep recovery keys credential-free

* fix(playback): remove derived tracking ownership

* fix(playback): preserve distinct recovery fallbacks

* fix(playback): reset resume for new sources

* fix(playback): preserve desktop recovery guidance

* docs(playback): clarify recovery policy exceptions

* fix(playback): reject stale progress updates

* fix(playback): keep protected recovery guidance neutral

* test(playback): cover stale progress output

* fix(playback): neutralize protected diagnostic copy

* fix(playback): harden runtime guidance ownership

* fix(playback): stabilize recovery application ownership

* fix(ci): classify playback util coverage

* fix(e2e): preserve playback fixture bytes

apps/web/src/assets/i18n/ko.json

@@ -551,6 +551,7 @@
             "DESCRIPTION": "The request may be blocked by CORS, mixed content, or provider header/proxy restrictions. MPV or VLC can often bypass browser-player access limits.",
             "PWA_DESCRIPTION": "The request may be blocked by CORS, mixed content, or provider header/proxy restrictions. The PWA cannot launch external players directly; use the Copy stream URL action and open it manually in MPV, VLC, IINA, or another player."
         },
+        "UNTRANSFERABLE_DESCRIPTION": "This protected stream requires playback configuration that cannot be transferred with the stream URL.",
         "DRM_OR_ENCRYPTION": {
             "TITLE": "This stream may be encrypted or DRM-protected",
             "DESCRIPTION": "The browser player cannot continue with the reported encryption/key error. External playback may still fail if provider DRM is required."
@@ -561,6 +562,17 @@
         },
         "NATIVE_FALLBACK_TITLE": "Open it in a native player instead",
         "INLINE_FAILURE_TITLE": "Copy the URL or try again",
+        "UNTRANSFERABLE_FAILURE_TITLE": "Protected playback could not continue",
+        "RECOMMENDATIONS_LABEL": "권장 복구 작업",
+        "ACTION_TRY_PLAYER": "{{player}} 사용해 보기",
+        "ACTION_TRY_PLAYER_HINT": "이 항목에만 임시로 적용되며 저장된 플레이어는 변경되지 않습니다",
+        "REASON_RETRY_TRANSIENT_FAILURE": "일시적인 로드 실패 후 같은 플레이어로 다시 시도합니다",
+        "REASON_RETRY_UNKNOWN_FAILURE": "오류에서 다른 호환 플레이어를 확인할 수 없어 다시 시도합니다",
+        "REASON_ALTERNATIVE_SOURCE_AVAILABLE": "같은 콘텐츠에 사용 가능한 다른 소스를 시도합니다",
+        "REASON_DIFFERENT_ENGINE_FAMILY": "이 플레이어는 다른 브라우저 재생 엔진을 사용합니다",
+        "REASON_EXTERNAL_CODEC_OR_CONTAINER_SUPPORT": "네이티브 플레이어는 더 많은 코덱과 컨테이너를 지원합니다",
+        "REASON_EXTERNAL_BROWSER_ACCESS": "네이티브 플레이어는 브라우저 접근 제한을 피할 수 있습니다",
+        "REASON_COMPATIBLE_DRM_PATH": "이 대상은 사용 가능한 암호화 데이터와 호환됩니다",
         "ACTION_OPEN_MPV": "Open in MPV",
         "ACTION_OPEN_VLC": "Open in VLC",
         "ACTION_OPEN_MPV_HINT": "configured player",