fix: tighten suppression_reason display guard, document unused since/until params

app/services/diagnose/pipeline.py

@@ -25,8 +25,8 @@ async def run_pipeline(
     entries: list[SearchResult],
     ctx: RetrievedContext,
     query: str,
-    since: str | None,
-    until: str | None,
+    since: str | None,   # reserved for future range-filtering in stage queries (#29 follow-up)
+    until: str | None,   # reserved for future range-filtering in stage queries (#29 follow-up)
     llm_url: str | None,
     llm_model: str | None,
     llm_api_key: str | None,

app/services/diagnose/synthesizer.py

@@ -48,7 +48,7 @@ def _build_hypothesis_block(ranked: list[RankedHypothesis]) -> str:
         conf_pct = int(h.confidence * 100)
         similar = (
             f"Yes — suppressed, {rh.suppression_reason}"
-            if rh.suppression_reason
+            if rh.suppress and rh.suppression_reason
             else "No"
         )
         novelty = f"{rh.novelty_score:.2f}"