feat(ai-assistant): odt support, document-to-lesson attach, upload UX fixes

- Add .odt (application/vnd.oasis.opendocument.text) as a supported upload
  format; extract text via JSZip + content.xml parsing
- Add attach_document_to_lesson agent tool so the AI can attach an uploaded
  document to a lesson as a downloadable material
- Instruct the agent to create a "Course Materials" lesson (first lesson of
  the first section) and attach the uploaded document to it on implementation
- Suppress hallucinated references: uploaded documents do not count as fetched
  URLs — omit the References section when no fetch_documentation_url calls
  were made
- Surface specific upload error snackbars (file_too_large, unsupported_file_type)
  instead of silently logging; fix generic fallback message
- Allow typing in the chat textarea while a document is uploading; only block
  Enter/send, not the whole input
- Fix retry endpoint to return the current run instead of erroring when the run
  is already active (queued/running/waiting_for_input/paused)
- Connect @cio/core Redis singleton in the jobs bootstrap so course-generation
  workers no longer fail with "The client is closed"
- Expose documentAssets (assetId + fileName) alongside documentText in
  AgentContext and pass it through both the chat route and course runner

apps/dashboard/src/lib/utils/translations/en.json

@@ -4613,7 +4613,10 @@
     "ask_ai_expand_aria": "Open Ask AI input",
     "ask_ai_input_aria": "Ask AI about this content",
     "quote_lesson_note": "Quote in assistant",
-    "attach_document": "Attach a document (PDF, DOCX, PPTX)",
+    "attach_document": "Attach a document (PDF, DOCX, PPTX, ODT)",
+    "upload_error_file_too_large": "File is too large. Maximum size is 5 MB.",
+    "upload_error_unsupported_type": "File type not supported. Please upload a PDF, DOCX, PPTX, or ODT file.",
+    "upload_error_generic": "Failed to upload document. Please try again.",
     "upgrade_to_upload": "Upgrade to upload documents",
     "tokens_exhausted": "Monthly AI token limit reached.",
     "tokens_exhausted_buy_more": "Buy more",