feat(MAT-46): Extract and post document annotations after voice calls

When a voice call ends and a document was loaded in the room, the bot
now analyzes the transcript for document-specific changes/corrections
and posts them as a structured "Dokument-Aenderungen" message. Returns
nothing if no document changes were discussed.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

bot.py

@@ -529,6 +529,8 @@ class Bot:
                 vs = self.voice_sessions.pop(room_id, None)
                 if vs:
                     transcript = vs.get_transcript()
+                    doc_context = vs.get_document_context()
+                    confluence_page_id = vs.get_confluence_page_id()
                     try:
                         await vs.stop()
                         logger.info("Voice session stopped for %s", room_id)
@@ -541,6 +543,16 @@ class Bot:
                             await self._send_text(room_id, f"**Anruf-Zusammenfassung:**\n\n{summary}")
                         except Exception:
                             logger.exception("Failed to post call summary for %s", room_id)
+                        # Extract and post document annotations if a document was discussed
+                        if doc_context:
+                            try:
+                                annotations = await self._extract_document_annotations(
+                                    transcript, doc_context, room_id)
+                                if annotations:
+                                    await self._send_text(room_id,
+                                        f"**Dokument-Aenderungen:**\n\n{annotations}")
+                            except Exception:
+                                logger.exception("Failed to post document annotations for %s", room_id)
 
                 # Leave the call too
                 self.active_calls.discard(room_id)
@@ -1735,6 +1747,57 @@ class Bot:
             logger.warning("Call summary LLM failed, falling back to raw transcript", exc_info=True)
             return "\n".join(lines[-20:])
 
+    async def _extract_document_annotations(
+        self, transcript: list[dict], doc_context: str, room_id: str
+    ) -> str | None:
+        """Extract document-specific changes/annotations discussed during a voice call.
+
+        Returns a structured list of changes, or None if no document changes were discussed.
+        """
+        lines = []
+        for entry in transcript[-30:]:
+            role = "Nutzer" if entry["role"] == "user" else "Assistent"
+            lines.append(f"{role}: {entry['text']}")
+        transcript_text = "\n".join(lines)
+
+        # Truncate document context for the prompt
+        doc_excerpt = doc_context[:8000]
+
+        if not self.llm:
+            return None
+
+        try:
+            model = self.room_models.get(room_id, DEFAULT_MODEL)
+            resp = await self.llm.chat.completions.create(
+                model=model,
+                messages=[
+                    {"role": "system", "content": (
+                        "Analysiere das Anruf-Transkript im Kontext des besprochenen Dokuments. "
+                        "Extrahiere ALLE konkreten Aenderungen, Korrekturen, Ergaenzungen oder "
+                        "Anmerkungen die der Nutzer zum Dokument gemacht hat.\n\n"
+                        "Format:\n"
+                        "- Jede Aenderung als Bullet Point\n"
+                        "- Zitiere den betroffenen Abschnitt/Satz wenn moeglich\n"
+                        "- Beschreibe was geaendert werden soll\n\n"
+                        "Wenn KEINE Dokument-Aenderungen besprochen wurden, antworte NUR mit: KEINE_AENDERUNGEN\n\n"
+                        "Antworte in der Sprache des Gespraechs."
+                    )},
+                    {"role": "user", "content": (
+                        f"Dokument:\n{doc_excerpt}\n\n---\n\nTranskript:\n{transcript_text}"
+                    )},
+                ],
+                max_tokens=800,
+            )
+            result = resp.choices[0].message.content.strip()
+            if "KEINE_AENDERUNGEN" in result:
+                logger.info("No document annotations found in call for %s", room_id)
+                return None
+            logger.info("Extracted document annotations for %s: %s", room_id, result[:200])
+            return result
+        except Exception:
+            logger.warning("Document annotation extraction failed", exc_info=True)
+            return None
+
     async def _send_text(self, room_id: str, text: str):
         await self.client.room_send(
             room_id,