Cannot login to Microsoft account protected by 2FA

Like any sane person, I protect my Microsoft account using 2FA/passkey/etc. But that seems to prevent me from logging into the Minecraft flatpak. Here's what happens:

1. I start the Minecraft flatpak.
2. I click on my username. A red box briefly appears in the top right saying "Something went wrong in the login process", even though it still appears to be working right now...
3. I click the Microsoft Login button.
4. It opens a new `Sign in to your account` window, prompting me to sign into my Microsoft account, so I enter my email address & click the Next button.
5. It then displays:
```
Face, fingerprint, PIN or security key
Your device will open a security window. Follow the instructions there to sign in.
```
Along with some moving dots suggesting it's doing something, and a greyed-out "Try again" button... But no new window appears, so it's just permanently stuck on that, until I close the window & give-up.

If I run it from the terminal, then after entering my email address it outputs the following:
```
[0625/175113.104116:INFO:LauncherAppRenderer.cpp(521)] OnContextReleased: no frame (unknown context), browser id=2
[0625/175113.105579:INFO:LauncherAppRenderer.cpp(521)] OnContextReleased: no frame (unknown context), browser id=2
[0625/175113.108229:INFO:LauncherAppRenderer.cpp(521)] OnContextReleased: no frame (unknown context), browser id=2
[0625/175113.111185:INFO:LauncherAppRenderer.cpp(69)] OnBrowserDestroyed: id=2
```

Not sure if it's related, but when first starting Minecraft it outputs the following:
```
~$ flatpak run com.mojang.Minecraft
https://launchermeta.mojang.com/v1/products/launcher/6f083b80d5e6fabbc4236f81d0d8f8a350c665a9/linux.json
[0625/174759.852343:INFO:main_context.cpp(134)] CEF initialized successfully.
[0625/174759.852394:INFO:main_context.cpp(136)] CEF version: 86.0.23+ga2c2edf+chromium-86.0.4240.193
sh: line 1: orca: command not found
[0625/174759.870863:ERROR:simple_backend_impl.cc(757)] Simple Cache Backend: wrong file structure on disk: 2 path: /home/USERNAME/.var/app/com.mojang.Minecraft/data/../.minecraft/webcache2/Code Cache/wasm
[0625/174759.871043:ERROR:simple_backend_impl.cc(757)] Simple Cache Backend: wrong file structure on disk: 2 path: /home/USERNAME/.var/app/com.mojang.Minecraft/data/../.minecraft/webcache2/Code Cache/js
Created browser window for reuse: 0x1400001
[0625/174759.913031:ERROR:sandbox_linux.cc(374)] InitializeSandbox() called with multiple threads in process gpu-process.
[0625/174759.921945:ERROR:simple_backend_impl.cc(757)] Simple Cache Backend: wrong file structure on disk: 2 path: /home/USERNAME/.var/app/com.mojang.Minecraft/data/../.minecraft/webcache2/Code Cache/wasm
[0625/174759.921983:ERROR:simple_backend_impl.cc(757)] Simple Cache Backend: wrong file structure on disk: 2 path: /home/USERNAME/.var/app/com.mojang.Minecraft/data/../.minecraft/webcache2/Code Cache/js
[0625/174759.927165:ERROR:disk_cache.cc(184)] Unable to create cache
[0625/174759.927202:ERROR:disk_cache.cc(184)] Unable to create cache
[0625/174800.274899:ERROR:simple_backend_impl.cc(757)] Simple Cache Backend: wrong file structure on disk: 2 path: /home/USERNAME/.var/app/com.mojang.Minecraft/data/../.minecraft/webcache2/Cache
[0625/174800.275075:ERROR:simple_backend_impl.cc(757)] Simple Cache Backend: wrong file structure on disk: 2 path: /home/USERNAME/.var/app/com.mojang.Minecraft/data/../.minecraft/webcache2/Cache
[0625/174800.275109:ERROR:disk_cache.cc(184)] Unable to create cache
[0625/174802.252641:WARNING:value_store_frontend.cc(43)] Reading mhjfbmdgcfjbbpaeojofohoefgiehjai.alarms from failed: IO error: .../LOCK: Access denied. (ChromeMethodBFE: 15::LockFile::5)
[0625/174938.941768:ERROR:gl_surface_presentation_helper.cc(259)] GetVSyncParametersIfAvailable() failed for 1 times!
```
(Except I replaced my username with USERNAME.)

Then when I click the Microsoft Login button it outputs:
```
Created browser window for reuse: 0x1400007
[0625/175008.824393:INFO:LauncherAppRenderer.cpp(51)] [Info: 2026-06-25 16:47:59.637091220: LauncherMain.cpp(107)] Initiated models
[0625/175008.824495:INFO:LauncherAppRenderer.cpp(51)] [Info: 2026-06-25 16:47:59.637309775: LauncherController.cpp(456)] Constructing launcher controller with workDir: /.../.minecraft, isActive: 0
[0625/175008.824554:INFO:LauncherAppRenderer.cpp(51)] [Info: 2026-06-25 16:50:07.270159102: LauncherAppRenderer.cpp(172)] Javascript bridge extended in OnWebKitInitialized.
[0625/175008.853671:INFO:LauncherAppRenderer.cpp(51)] [Info: 2026-06-25 16:50:08.853652916: LauncherAppRenderer.cpp(310)] OnContextCreated: non-main frame, browser id=2
```

Reproduce the Microsoft login flow with 2FA or a passkey in the com.mojang.Minecraft Flatpak, then start with the CEF and LauncherAppRenderer.cpp log entries reported in the issue. Trace the security-window step and verify that authentication completes without leaving the login window stuck.

Written by the indexing model from the issue text.