Fix local network access on Android 17

[Hunter-The-Furry]

What changed

Android 17 requires apps targeting SDK 37 to request local network access before connecting to devices on the LAN.

This adds the ACCESS_LOCAL_NETWORK permission and requests it at startup on Android 17+. Older Android versions keep the existing behavior.

Why

Without the permission, connections to a local TrueNAS server can just time out even though the server is reachable from the browser.

This may also be the cause of #96 if that GrapheneOS device is up to date and running Android 17, since the reported symptoms are very similar.

Tested

Built and installed the GitHub debug APK on a physical Android 17 device and confirmed I can connect and log in to a local TrueNAS instance after granting the Local Network permission.

testGithubDebugUnitTest and assembleGithubDebug pass.

lintGithubDebug still fails on 3 existing UnusedMaterial3ScaffoldPaddingParameter errors in unrelated files. This change does not add any new lint warnings.

[Hunter-The-Furry]

A few follow-up ideas I left out of this PR so it stays focused:

• The notification and local-network permission prompts can both happen during startup right now. It may be worth handling those in sequence so they don't compete with each other.
• If Local Network permission is denied, the app still starts, but local instances will just fail to connect. A more specific message there, with a shortcut to app settings, would probably be nicer.
• It might also make sense to only ask for Local Network access when a local instance actually needs it. Saved instances that reconnect on startup make that a bit more involved, though.

I left these out since they felt more like follow-up UX work than part of the actual connection fix.