fix(logging): interpolate log fields instead of passing an object

Electron's console bridge stringifies each console argument on its way to
the journal, so `console.log('msg:', { a, b })` arrives as
`msg: [object Object]` and every field is lost.

That cost a debugging session today: a cassette-state publish that had
in fact applied an operator refill correctly looked from the journal like
nothing had happened, because the d-tag, event id and stamp were all
inside the object.

Three call sites, the only ones in the renderer passing an object. The
publish line now also carries seq and the applied-op count, which are the
two things worth knowing when an operation seems not to have landed.

Recorded in CLAUDE.md's debugging invariants so it does not come back.

apps/machine/src/services/operator-config.ts

@@ -147,7 +147,7 @@ export async function startOperatorConfigService(
       },
     }
   )
-  console.log('[OperatorConfig] Subscribed:', { dTag, subscriptionId })
+  console.log(`[OperatorConfig] Subscribed: d=${dTag} sub=${subscriptionId}`)
 
   const heartbeat = setInterval(() => {
     publishCassettesState(cfg, api, machineId).catch((err) =>
@@ -342,6 +342,9 @@ async function publishCassettesState(
 
   await cfg.nostrClient.publish(event)
   await api.markStatePublished(createdAt)
-  console.log('[OperatorConfig] cassettes-state published:', { dTag, eventId: event.id, createdAt })
+  console.log(
+    `[OperatorConfig] cassettes-state published: id=${event.id.slice(0, 12)}… ` +
+      `created_at=${createdAt} seq=${seq} applied_ops=${appliedOps.length} d=${dTag}`
+  )
   return true
 }

apps/machine/src/services/operator-fees.ts

@@ -132,7 +132,7 @@ export async function startOperatorFeesService(
       },
     }
   )
-  console.log('[Fees] Subscribed:', { dTag, subscriptionId })
+  console.log(`[Fees] Subscribed: d=${dTag} sub=${subscriptionId}`)
 
   return {
     stop: () => cfg.nostrClient.unsubscribe(subscriptionId),