- research_runs: split the synthesis evidence budget evenly across notes so a
small context still keeps a slice of every research step instead of dropping
the later steps after the earliest ones fill the budget.
- research_runs: shield the research question and approved plan before placing
them in the decision and synthesis prompts, so a closing delimiter in either
cannot escape its block and inject sibling sections.
- research_runs: redact bearer authorization tokens from public search queries.
- studio_db: include attachments in the research-message change check and guard
direct attachment deletion, so server-managed research prompts and responses
cannot be mutated through the attachment paths.
- chat_history: map the protected-message conflict on attachment deletion to 409.
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