Add stale recovery to tracker mapping worker

The tracker-mapping worker clears mapping_requested_at at claim time, so
a crash or hard failure between Process phases left the pattern dequeued,
unmapped, and with nothing to re-trigger it. Only an incidental sibling
remap could rescue it, so a lone pattern could stay stranded forever.

Implement the worker.StaleRecoverer interface, mirroring the enrichment
worker. ResetStaleMappings re-arms rows that were claimed but never
assigned a catalog row (common_tracker_pattern_id IS NULL) once idle past
a configurable window; a successful Process always assigns one via the
unmatched fallback, so the predicate cleanly detects interrupted runs and
self-heals after a single pass. ClearMappingRequestedAt now bumps
updated_at so the stale clock starts at claim time and the sweep never
recycles an in-flight claim.

Plumb a StaleAfter knob (default 600s) through the config struct, builder
env var, probod wiring, and Helm templates.

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

pkg/bootstrap/builder.go

@@ -249,6 +249,7 @@ func (b *Builder) Build() (*probodconfig.FullConfig, error) {
 			TrackerMappingWorker: probodconfig.TrackerMappingWorkerConfig{
 				Interval:       b.getEnvIntOrDefault("TRACKER_MAPPING_INTERVAL", 10),
 				MaxConcurrency: b.getEnvIntOrDefault("TRACKER_MAPPING_MAX_CONCURRENCY", 3),
+				StaleAfter:     b.getEnvIntOrDefault("TRACKER_MAPPING_STALE_AFTER", 600),
 				AgentTimeout:   b.getEnvIntOrDefault("TRACKER_MAPPING_AGENT_TIMEOUT", 45),
 				AgentMaxTurns:  b.getEnvIntOrDefault("TRACKER_MAPPING_AGENT_MAX_TURNS", 4),
 			},