* fix(agents): suppress Write/Edit failed warning on response-timeout false-failure (#55424)
Reporter sees '⚠️ Write failed' / '⚠️ Edit failed' warnings on Feishu (and other channels) even though the file was 100% saved successfully (8 of 8 verified writes succeeded; warning shown for all 8). Source path: tool-mutation records lastToolError.timedOut=true with a fileTarget when a write/edit tool ack reply times out after the disk mutation has already completed, then resolveToolErrorWarningPolicy goes through the default mutating-tool branch and emits the misleading failure summary.
Add a narrow gate inside resolveToolErrorWarningPolicy that suppresses the warning only when both lastToolError.timedOut is true AND lastToolError.fileTarget is defined. fileTarget is set by tool-mutation.ts only for the write/edit family (FILE_MUTATING_TOOL_NAMES), so this branch never matches exec/message/cron/gateway mutating-tool timeouts where the disk-write idempotency reasoning does not apply. Real file failures (no timeout) and timeouts without recorded fileTarget keep their visible warnings.
* fix: recover completed write timeouts safely
* fix: bound write timeout recovery precheck
* fix: type write recovery precheck fallback
* test: complete write recovery result mock
* test: isolate e2e timeout fixture shims
* test: stabilize e2e timeout fixture path
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Co-authored-by: Peter Steinberger <steipete@gmail.com>
