Constant MCP_REMEMBER_BATCH_PROGRESS_EMIT_EVERY 

pub const MCP_REMEMBER_BATCH_PROGRESS_EMIT_EVERY: usize = 25;

How often (in items processed) memory_remember_batch emits a progress event during the embed loop. Plan §6 P3 spec: “every 25 rows”. Set to 25 so a 51-item batch emits at items 25 + 50 + the final terminal event.