feat(FN-1500): suppress per-tool triage stdout spam

- Add tool-specific toolOutput handler in triage agent to filter per-tool output
- Add test coverage for tool output suppression behavior
- Suppress console spam from read_file, Read, glob, Grep tools during triage runs
- Update memory documentation with Vitest expect.any(Number) pitfall

.changeset/fn-1500-suppress-triage-tool-stdout.md

@@ -0,0 +1,11 @@
+---
+"@gsxdsm/fusion": patch
+---
+
+Suppress per-tool triage stdout spam during `fn dashboard` / `fn serve` runtime
+
+Triage agent tool calls no longer emit per-tool lines like `[triage] FN-XXX tool: read` to stdout. This reduces terminal noise while preserving:
+- Internal observability via task agent logs (`fn task logs`)
+- Stuck-task heartbeat tracking via `StuckTaskDetector.recordActivity()`
+
+This aligns with project memory guidance to keep engine diagnostics high-signal and avoid noisy low-value terminal spam.