v0.7.6

Fixed

• <sender_context> metadata in user prompts made models emit empty replies with no tool calls — OpenAB-style harnesses prepend a <sender_context>{…json…}</sender_context> block to the user message. Several local LLMs (observed on Qwen3-Coder via Ollama) interpret the XML wrapper as a directive and stall — the model returns empty content with no tool calls, which surfaces upstream as "the agent doesn't reply" and "the agent doesn't know about brain/KB". engine::strip_sender_context now detects the block, removes it from the forwarded user text, and logs the captured inner string at debug level for traceability. Both the ACP (handle_acp_prompt) and A2A (handle_message_send) entry points strip before the empty-prompt guard and before passing to session_prompt. Four unit tests cover the leading-block case, the no-block passthrough, an unterminated open tag, and the all-metadata edge case. Reviewer-flagged by openab-rukawa.