Mobile notifications for iOS (#210)

* mobile: wire notification registration and listener

* implement backend components for push notifications

* refactor: agentic comment cleanup

* docs: use proper module name for particle processor

* set required env variables for push notifications

* bump version

* fix: always upsert push token on mobile start

* Revert "fix: always upsert push token on mobile start"

This reverts commit 90ff18a788.

* send push notifications regardless of online status

go/internal/db/redis.go

@@ -1,8 +1,8 @@
 package db
 
-// Shared database namespaces used across services
-// FIX: Use separate redis instance. We start with higher number because use this same instance in helios.
+// FIX: move to a dedicated Redis instance. The high DB numbers exist because
+// this instance is shared with helios.
 const (
 	RedisDBAuth   = 4 // auth sessions
-	RedisDBPusher = 5 // dedicated to pusher state (presence, pub/sub)
+	RedisDBPusher = 5 // presence, pub/sub
 )