[BUG]: Paperclip attachments added mid-session ignored (non-RAG)

### How are you running AnythingLLM? AnythingLLM desktop app ### What happened? Paperclip attachments added mid-session ignored (Chat and Agent modes). This is not a RAG / workspace embedding issue. Initial batch works; mid-session addition does not. ### Environment: AnythingLLM (1.14.0) + MiniMax-M3, Windows 11 Laptop: i7-13620H, 32 GB RAM, GeForce RTX 4060 Laptop GPU (8 GB) Workspace Agent LLM Provider: System Default Vector Database Provider: LanceDB ### Are there known steps to reproduce? ### Reproduction 1. Start a new chat thread. 2. Attach N files (PDF or other) via the paperclip button before sending the first message. 3. Send a question. Agent correctly references the attached files. 4. During the same session, attach an additional file via the paperclip button. 5. Send a follow-up question that requires knowledge of all files (including the newly attached one) or just ask agent about all attachments in the current context. **Expected** The agent references all files, including the one added in step 4. **Actual** The agent references only the files attached in step 2. The file added in step 4 is ignored, even though it appears in the UI’s attached-files list. <img width="1681" height="1564" alt="Image" src="https://github.com/user-attachments/assets/65e4410d-7bdd-400e-8dc7-adef71c4ca02" /> ### LLM Provider & Model (if applicable) Tried both LLM Providers LLM Provider: Minimax → Chat Model Selection: MiniMax-M3 LLM Provider: Generic OpenAI → Chat Model Selection: MiniMax-M3 ### Embedder Provider & Model (if applicable) Embedding Provider: AnythingLLM Embedder → multilingual-e5-small