[PM-40402] SocketTimeoutException trying to connect to directly attached IPv6 addresses

### Steps To Reproduce

1. Host a bitwarden server on your local network, accessible only over IPv6 (for example, some IPv6 ULA such as `fdd4:aa51:eed9:426:9f99:938b:ebf9:7433`, accessible via `bitwarden.example.com`, which you'll see the in stacktrace below.).
2. With your android phone connected to the same local network: open bitwarden, on the login screen, select "Self-hosted", tap "Self-hosted", and enter the url of your server (in this example: `https://bitwarden.example.com`).
3. Try to log in. You'll experience a delay after pressing "Continue" on the login screen, but you will eventually make it to the master password prompt screen.
4. On the master password prompt screen: enter your master password and click "Log in with master password". After 10 seconds of "Logging in...", you'll get a popup that says "An error has occurred. We were unable to process your request. Please try again or contact us." If you click "Share error details", you'll see a stacktrace of a `SocketTimeoutException` (full trace below).

### Expected Result

I expect to be able to log into my bitwarden server.

### Actual Result

Here's the stack trace:

```
Stacktrace:
java.net.SocketTimeoutException: failed to connect to bitwarden.example.com/fdd4:aa51:eed9:426:9f99:938b:ebf9:7433 (port 443) from /fdd4:aa51:eed9:426:9f99:93b5:4d8:4a2e (port 38658) after 10000ms
libcore.io.IoBridge.connectErrno(IoBridge.java:235)
libcore.io.IoBridge.connect(IoBridge.java:179)
java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:142)
java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:390)
java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:230)
java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:212)
java.net.SocksSocketImpl.connect(SocksSocketImpl.java:436)
java.net.Socket.connect(Socket.java:646)
ev1.i(r8-map-id-01e002bd0632bb5cc7de20747ff74afc7c2ccce2c9b98107678ea7daf8b79b97:77)
ev1.d(r8-map-id-01e002bd0632bb5cc7de20747ff74afc7c2ccce2c9b98107678ea7daf8b79b97:38)
r63.a(r8-map-id-01e002bd0632bb5cc7de20747ff74afc7c2ccce2c9b98107678ea7daf8b79b97:3)
ia.a(r8-map-id-01e002bd0632bb5cc7de20747ff74afc7c2ccce2c9b98107678ea7daf8b79b97:67)
ia.run(r8-map-id-01e002bd0632bb5cc7de20747ff74afc7c2ccce2c9b98107678ea7daf8b79b97:82)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1100)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
java.lang.Thread.run(Thread.java:1572)

Version: 2026.6.1 (21713)
Device: 📱 google Pixel 6 🤖 17@37 📦 prod -fdroid
CI: 🧱 commit: bitwarden/android/release/2026.6-rc57@e5ee43f68773f9fe20bec3dd664781d65b804967
💻 build source: bitwarden/android/actions/runs/28253991408/attempts/1
```

### Screenshots or Videos

_No response_

### Additional Context

The last version of the app where this worked was 2026.5.0. I tested 2026.6.1, 2026.6.0, and 2026.5.1 and confirmed they do not work.

I bisected and found that this was introduced by https://github.com/bitwarden/android/pull/6916, which upgraded the android sdk from 36 to 37. One consequence of sdk version 37 is that [local network permission](https://developer.android.com/privacy-and-security/local-network-permission) is now disabled by default. The bitwarden android app only requests local network access if the address we're connecting to [is a "site local address", as returned by `InetAddress.isSiteLocalAddress`](https://github.com/bitwarden/android/blob/v2026.6.1-bwpm/network/src/main/kotlin/com/bitwarden/network/interceptor/PermissionInterceptor.kt#L42). Here are the implementations for ipv4 and ipv6:

- ipv4: https://android.googlesource.com/platform/libcore/+/android-17.0.0_r1/ojluni/src/main/java/java/net/Inet4Address.java#239
- RFC 1918 calls these "private" addresses
- ipv6: https://android.googlesource.com/platform/libcore/+/android-17.0.0_r1/ojluni/src/main/java/java/net/Inet6Address.java#365
- This implements ipv6's long-deprecated "site local addresses". The modern replacement are unique local addresses (ULAs). Wikipedia has a decent history: https://en.wikipedia.org/wiki/Unique_local_address#History).

However, I don't think the correct fix here is to just add "is ula?" to the check. I believe the intent of the code is to check "would android block connections to this ip address?", which android conveniently documents on their [Local Network Definition](https://developer.android.com/privacy-and-security/local-network-definition) page. Fun fact: this reveals that our ipv4 check is likely wrong as well (android blocks link local and CGNAT addresses, which are not detected by [`Inet4Address.isSiteLocalAddress`](https://android.googlesource.com/platform/libcore/+/android-17.0.0_r1/ojluni/src/main/java/java/net/Inet4Address.java#239)). The IPv6 check is even harder to implement, as it's not just a comparison against static subnets, it depends on your routing table.

AFAICT, there's no easy way to implement this check (I've asked android for advice on this in https://issuetracker.google.com/issues/534973523). I think one correct way to do it is to just try and check for the error reason afterwards with `android_getnetworkblockedreason`, but I guess that requires trying and waiting for a timeout, and it requires using the NDK.

Perhaps the least odious approach would be to prompt the user for local network permission if they select "Self-hosted"? Or catching `SocketTimeoutException` and warning the user that they might need to grant the "Nearby devices" permission?

### Build Version

2026.6.1 (21713)

### What server are you connecting to?

Self-host

### Self-host Server Version

I promise this is not relevant

### Environment Details

- Device: Google Pixel 6
- Android version: 17

### Issue Tracking Info

- [x] I understand that work is tracked outside of Github. A PR will be linked to this issue should one be opened to address it, but Bitwarden doesn't use fields like "assigned", "milestone", or "project" to track progress.

Start in network/src/main/kotlin/com/bitwarden/network/interceptor/PermissionInterceptor.kt and review the Android local-network permission definition plus PR #6916. Reproduce the self-hosted IPv6 ULA login failure on the reported Android version, then determine and implement the permission or error handling that avoids the timeout. Done means the reported self-hosted IPv6 login succeeds and behavior is verified for the affected address cases.

Written by the indexing model from the issue text.