feat(VocabService, localization, VocabLessonView): extend assistant wait feedback and timeout duration

- Increased the timeout duration for the language assistant from 30 seconds to 120 seconds to accommodate longer processing times.
- Added new localization strings across multiple languages (Cebuano, German, English, Spanish, French) to provide user feedback during the assistant's wait period, enhancing clarity and user experience.
- Implemented a visual waiting indicator in VocabLessonView to inform users that the assistant is still processing their request, improving overall interaction quality.

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

@@ -697,6 +697,9 @@
                 "languageAssistantInputPlaceholder": "Ask a lesson question or write your own sentence for correction.",
                 "languageAssistantSend": "Send to assistant",
                 "languageAssistantSending": "Getting answer ...",
+                "languageAssistantWaitingTitle": "The language assistant is still working.",
+                "languageAssistantWaitingBody": "Local models like Ollama can take a few seconds, especially while the model is loading.",
+                "languageAssistantWaitingElapsed": "Waiting time: {seconds}s",
                 "languageAssistantError": "The language assistant could not answer right now.",
                 "languageAssistantPresetExplainStart": "Please explain the main patterns and grammar in the lesson",
                 "languageAssistantPatternHint": "Focus especially on this pattern",