Stop auto-creating org third parties on mapping

The tracker-mapping worker materialized a per-org ThirdParty for every
categorized tracker, linking or creating one through heuristic and
disambiguation-agent matching. Concurrent mapping of two patterns for
the same common third party raced the load-then-create check and left
duplicate org third parties with the same name.

Reduce the worker to catalog resolution only: it resolves the shared
common_tracker_pattern_id / common_third_party_id link and leaves
third_party_id untouched, preserving any link set elsewhere. Org third
parties will instead be created through an explicit per-vendor import
action added in a later commit.

Remove resolveOrgThirdParty, prepareOrgThirdParty, the sibling
direct-link signal, and the disambiguation-agent wiring (including its
constructor parameter and buildTrackerAgents return), and update the
worker tests to assert the catalog link is resolved while third_party_id
is preserved.

Signed-off-by: Émile Ré <emile@probo.com>

pkg/probod/probod.go

@@ -321,7 +321,7 @@ func (impl *Implm) Run(
 		return err
 	}
 
-	trackerMappingCfg, trackerEnrichmentCfg, thirdPartyDisambiguationCfg, err := impl.buildTrackerAgents(l, tp, r)
+	trackerMappingCfg, trackerEnrichmentCfg, err := impl.buildTrackerAgents(l, tp, r)
 	if err != nil {
 		return err
 	}
@@ -775,7 +775,6 @@ func (impl *Implm) Run(
 		pgClient,
 		l,
 		trackerMappingCfg,
-		thirdPartyDisambiguationCfg,
 		time.Duration(impl.cfg.TrackerMappingWorker.StaleAfter)*time.Second,
 		worker.WithInterval(time.Duration(impl.cfg.TrackerMappingWorker.Interval)*time.Second),
 		worker.WithMaxConcurrency(impl.cfg.TrackerMappingWorker.MaxConcurrency),