Report user presence on app lifecycle transitions (#5838)

* Report user presence on app lifecycle transitions

Adds a PresenceReporter driven by the app lifecycle handlers and the sharePresence setting: online when foreground-active and sharing, unavailable when backgrounded and sharing, offline when not sharing. Sends are immediate, deduped, and serialized latest-wins. Background app refresh and the NSE seed the process presence to offline so their sync requests carry no presence side effect. Presence rides on the SDK's process-global state, so every sync path is covered without touching sync lifecycle.

Signed-off-by: Jared L <48422312+lhjt@users.noreply.github.com>

* Add presence reporter tests

Pins the presence reporter invariants: the never-online sweep with sharing off, an immediate online send on foreground-active, dedupe of repeated states, latest-wins ordering of serialized sends, and the NSE offline seed.

Signed-off-by: Jared L <48422312+lhjt@users.noreply.github.com>

* wip: address review comments

Signed-off-by: Jared L <48422312+lhjt@users.noreply.github.com>

* refactor: remove obsolete presence heartbeat

Remove the shared activity snapshot, heartbeat refresh, and notification-extension freshness policy while retaining the session-scoped presence service and its serialized lifecycle reporting. Restore the NSE's intermediate one-time offline seed so the cleanup remains buildable ahead of the final sync-presence correction.

Signed-off-by: Jared L <48422312+lhjt@users.noreply.github.com>

* fix: make notification extension presence-neutral

Configure the built NSE client with offline sync presence without sending an immediate presence update. Keep notification setup non-fatal when presence configuration fails and remove the temporary production test seam.

Signed-off-by: Jared L <48422312+lhjt@users.noreply.github.com>

* chore: restore application lifecycle logging

Restore the pre-existing foreground lifecycle diagnostics that were removed during the presence refactor. Keep presence reporting session-scoped and clarify that background refresh configures the client's sync presence without an immediate update.

Signed-off-by: Jared L <48422312+lhjt@users.noreply.github.com>

---------

Signed-off-by: Jared L <48422312+lhjt@users.noreply.github.com>

NSE/Sources/NSEUserSession.swift

@@ -79,6 +79,12 @@ final nonisolated class NSEUserSession: NSEUserSessionProtocol {
             .homeserverUrl(url: homeserverURL)
         
         baseClient = try await clientBuilder.build()
+        
+        do {
+            try await baseClient.setPresence(presence: .offline, immediate: false)
+        } catch {
+            MXLog.error("Failed configuring offline presence before notification processing with error: \(error)")
+        }
         delegateHandle = try baseClient.setDelegate(delegate: ClientDelegateWrapper())
         
         try await baseClient.restoreSessionWith(session: credentials.restorationToken.session,