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

packages/ai-assistant/src/prompt/teacher.ts

@@ -279,6 +279,8 @@ If this conversation contains any successful \`fetch_documentation_url\` tool re
 
 When any \`fetch_documentation_url\` results exist in this conversation, **every** lesson you create or update via \`update_lesson_content\` MUST end with a References section so the teacher can verify your sourcing. Skip the References section ONLY when zero docs have been fetched in the entire conversation.
 
+**Uploaded documents do NOT count as fetched documentation for the purposes of References.** If the only source material is an uploaded document (no \`fetch_documentation_url\` calls were made), omit the References section entirely — do not fabricate URLs or cite the document by a made-up link.
+
 Format the section as the last block of the lesson HTML, in this exact shape:
 
 \`\`\`html
@@ -431,11 +433,30 @@ export function buildTeacherContextMessage(
     contextLines.push(exerciseInfo);
   }
   if (context.documentText) {
+    const docAssets = context.documentAssets ?? [];
+    const assetLines = docAssets
+      .filter((d) => d.assetId)
+      .map((d) => `- documentId: ${d.documentId}, fileName: ${d.fileName}`)
+      .join('\n');
+
+    const courseMaterialsInstruction =
+      assetLines.length > 0
+        ? `\n\nWhen implementing a course plan, create a lesson titled **"Course Materials"** as the **first lesson of the first section**. Give it no text content. Then immediately call \`attach_document_to_lesson\` for each document listed below to attach the original file to that lesson:\n${assetLines}`
+        : '';
+
     contextLines.push(
-      `The teacher has uploaded a document. Use this content as the source material for course planning and content generation:\n\n<document>\n${context.documentText}\n</document>`
+      `The teacher has uploaded a document. Use this content as the source material for course planning and content generation:${courseMaterialsInstruction}\n\n<document>\n${context.documentText}\n</document>`
     );
   }
-  if (context.existingSectionCount && context.existingSectionCount > 0) {
+  if (context.isContentGroupingEnabled === false) {
+    contextLines.push(
+      `**Content grouping is DISABLED for this course.** Lessons and exercises are displayed as a flat ordered list — sections are invisible to students and teachers. Follow these rules strictly:\n` +
+        `- Do NOT plan or create multiple sections. Use exactly ONE section as a technical container for all content.\n` +
+        `- In \`generate_course_plan\`, output a single section whose title matches the course title. Place all lessons and exercises as items inside that one section, ordered sequentially (order 0, 1, 2, …).\n` +
+        `- When implementing a plan, create that one section first, then add every lesson and exercise into it with strictly ascending \`order\` values (0, 1, 2, …). The order field is the only thing that controls the visible sequence.\n` +
+        `- Never call \`create_section\` more than once for this course.`
+    );
+  } else if (context.existingSectionCount && context.existingSectionCount > 0) {
     contextLines.push(
       `This course already has ${context.existingSectionCount} sections. When creating new sections, set their order values starting after the existing sections.`
     );

packages/ai-assistant/src/types.ts

@@ -43,7 +43,11 @@ export interface AgentContext {
   exerciseTitle?: string;
   documentId?: string;
   documentText?: string;
+  /** Metadata for documents attached to this conversation — used to attach originals to lessons. */
+  documentAssets?: { documentId: string; assetId: string | null; fileName: string }[];
   existingSectionCount?: number;
+  /** When false, content grouping is disabled: lessons/exercises are displayed as a flat ordered list and sections are hidden from students. */
+  isContentGroupingEnabled?: boolean;
 }
 
 // ─── Course Plan (generated by the agent in Plan Mode) ───────────────────────
@@ -215,11 +219,12 @@ export const MAX_STEPS_PER_ROUND = 15;
 export const SUPPORTED_DOCUMENT_TYPES = [
   'application/pdf',
   'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
-  'application/vnd.openxmlformats-officedocument.presentationml.presentation'
+  'application/vnd.openxmlformats-officedocument.presentationml.presentation',
+  'application/vnd.oasis.opendocument.text'
 ] as const;
 
 /** Supported file extensions for document upload */
-export const SUPPORTED_DOCUMENT_EXTENSIONS = ['.pdf', '.docx', '.pptx'] as const;
+export const SUPPORTED_DOCUMENT_EXTENSIONS = ['.pdf', '.docx', '.pptx', '.odt'] as const;
 
 /** Token cost estimation heuristics (tokens per item) */
 export const TOKEN_COST_ESTIMATES = {