handleToolExecutionStart() flushed pending block replies and then called
onBlockReplyFlush() as fire-and-forget (`void`). This created a race where
fast tool results (especially media on Telegram) could be delivered before
the text block that preceded the tool call.
Await onBlockReplyFlush() so the block pipeline finishes before tool
execution continues, preserving delivery order.
Fixes#25267
Co-authored-by: Cursor <cursoragent@cursor.com>
Pre-existing test mocks lacked pendingMessagingMediaUrls and
messagingToolSentMediaUrls fields added by the media dedup feature,
causing runtime errors in handleToolExecutionEnd.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Cover three integration points where media dedup could silently regress:
- trimMessagingToolSent FIFO cap at 200 entries
- buildReplyPayloads media filter wiring (new test file)
- followup-runner messagingToolSentMediaUrls filtering
