fix: update scene phase change logic

[pwltr]

When the app is backgrounded, the process can be either suspended or terminated. (Overdue) Refresh timers for exchange rates and orders will run on resume, so scene phase no longer triggers them and only clears delivered notifications. Peer reconnection is triggered when becoming active so channel peers come back quickly instead of waiting for LDK’s internal timer. The Lightning node is no longer stopped in background, so after a suspend it can resume without a full restart. In case of termination, all of the normal startup logic will run.

Changes

• remove unnecessary logic on scene phase .background/.foreground (also fixes a case where node fails to start after being backgrounded)
• explicitly reconnect to peers instead of relying on background timer

Screenshots

Simulator.Screen.Recording.-.iPhone.17.-.2026-03-04.at.11.21.02.mov

QA Notes

Should be able to use the app normally immediately after resuming including Lightning channels.

Inactive only (no background)

• Example: User opens Control Center or an overlay; scene goes .inactive then .active. Process is not suspended.
• Expect: App continues normally.

App backgrounded (suspended, not killed)

• Process: Remains in memory; execution is suspended.
• Scene phase: Goes to .background. We do not stop the Lightning node; it simply stops receiving CPU.
• On resume: Scene goes .inactive then .active. Run loop runs again; LDK resumes (e.g. timer_tick, peer handling); (overdue) timers fire (fe. refresh rates, orders).
• Expect: One refresh wave (rates + orders) when returning. No node stop in logs. Balances and spending work without restart.

App killed (swiped away or terminated by system)

• Process: Exits. All in-memory state is lost.
• On next launch (cold start): New process. Wallet/node start via handleWalletExistsChange → startWallet(), not from scene phase. View models perform an initial refresh in init.
• Expect: App starts normally (cold start).