fix: isolate per-adapter search failures in the pipeline match loop

Wrap each adapter's search() call in the match stage in try/except so
a down source (dead slskd, Qobuz auth error, etc.) contributes no
candidates instead of crashing run_pipeline and killing the worker.

worker/lyra_worker/pipeline.py

@@ -126,7 +126,12 @@ def run_pipeline(
     _set_state(conn, job_id, "matching", "match")
     found: list[Candidate] = []
     for adapter in adapters:
-        for c in adapter.search(target):
+        try:
+            results = adapter.search(target)
+        except Exception as e:  # a down source contributes no candidates, never crashes the job
+            print(f"pipeline: adapter {adapter.name} search failed: {e}", flush=True)
+            continue
+        for c in results:
             found.append(replace(c, source_tier=adapter.tier, confidence=score_confidence(target, c)))
     _persist_candidates(conn, job_id, found)