android: do not restore last playing when opened from link

[gabparrot]

Cold start from a YouTube link in another app always resumed the last-played video instead of opening the linked video, even with "Restore last playing on start" enabled (#158). The same root cause — incoming intent URLs being dropped on cold start — is also why deep links were ignored entirely (#188).

Linking.getInitialURL() was never called in app/index.tsx, so the Android intent URL was dropped on cold start. The first webview onload then unconditionally triggered window.NouTube.restoreLastPlaying() because the only guard was the user setting.

Call Linking.getInitialURL() on mount and route through the existing openSharedUrl path. When a deep link resolves before onload, the existing ui$.url observer in MainPageContent.tsx already flips the restored flag so restoreLastPlaying is skipped — no extra guard needed.

Warm-start Linking events, share-intent path, and the user-facing setting are unchanged.

Closes #158
Closes #188

[rnons]

have you tested opening a second deep link, in my test, noutube was stuck with the 1st deep link