[Fix] Fix for TileShell Not Starting on Ubuntu 26.04 - GNOME 50

## Fix for TileShell Not Starting on Ubuntu 26.04

On Ubuntu 26.04, TileShell may fail to start because the extension is not being enabled with the following command:

```bash
/usr/bin/gnome-extensions enable tilingshell@ferrarodomenico.com
```

The solution that worked for me was:

### 1. Install the extension

Install **TileShell 18.0-candidate** (or the latest stable release) into:

```text
~/.local/share/gnome-shell/extensions/
```

### 2. Check whether user extensions are globally disabled

If this setting is `true`, no user extensions will be loaded, so the `enable` command will appear to have no effect.

Check the current value:

```bash
gsettings get org.gnome.shell disable-user-extensions
```

If it returns `true`, enable user extensions again:

```bash
gsettings set org.gnome.shell disable-user-extensions false
```

### 3. Enable the extension

```bash
/usr/bin/gnome-extensions enable tilingshell@ferrarodomenico.com
```

### 4. Compile the GSettings schemas

```bash
glib-compile-schemas ~/.local/share/gnome-shell/extensions/tilingshell@ferrarodomenico.com/schemas/
```

### 5. Restart your user session

Log out and log back in to reload GNOME Shell and activate the extension.

----

$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=26.04
DISTRIB_CODENAME=resolute
DISTRIB_DESCRIPTION="Ubuntu 26.04 LTS"

robson@vaiodefault:~
$ echo $XDG_SESSION_TYPE
wayland

$ gnome-shell --version
GNOME Shell 50.1

Reproduce the startup failure on Ubuntu 26.04 with GNOME Shell 50.1 under Wayland, starting with the gnome-extensions and gsettings commands shown in the issue. Investigate the extension installation and enablement behavior; done means TileShell starts successfully after installation without requiring the reported workaround.

Written by the indexing model from the issue text.