Please help me install and set up "Scarlet" from veered.org on my own computer or server.

What it is: A KDE Connect fix so your phone's link to COSMIC recovers by itself. It runs on: The COSMIC desktop (Pop!_OS).
Project page: https://veered.org/kdeconnect-cosmic-fix/
Source code download (zip): https://veered.org/kdeconnect-cosmic-fix/scarlet-kdeconnect-fix.zip

How I'd like you to help:
1. First ask me what you need to know: my operating system and version, my desktop environment if it matters, whether I'm comfortable with the terminal, and any accounts or hardware this project needs.
2. Then take me through it one step at a time. For each command, say briefly what it does, and wait for me to paste back the result before moving on.
3. Before any step that changes system settings, uses sudo, or edits an existing configuration file, tell me, and have me make a backup first.
4. If something fails, help me work out why. If the instructions below don't fit my system, say so rather than guessing.
5. At the end, show me how to check that it works, and how to uninstall it.

The project is shared as-is by its author, with no warranty. If we find a problem in the project itself, please help me write a short, clear note I can send to support@veered.org.

Here is the project's documentation (README files from the download):

===== README.md =====
# KDE Connect Fix for COSMIC (TLS Role Patch) (Scarlet)

*Why Scarlet? The scarlet thread that ties two things together: here, your phone to your computer.*

**Runs on** the COSMIC desktop (Pop!_OS).

**Version 1.0.**

Part of [Veered](https://veered.org): free tools, shared as-is. Questions: support@veered.org

**KDE Connect links your phone to your computer.** With it, text messages and other
phone notifications pop up on the desktop, you can send files between the two, and the
phone can act as a remote control. It is free, and there is an app for Android and one
for the desktop.

**The problem this fixes:** on the COSMIC desktop the link keeps dropping, and once it
drops the notifications quietly stop. The only way to get them back is to pick up the
phone and open the KDE Connect app again.

**Why it happens, in one line:** when the two sides introduce themselves to each other,
the desktop was speaking in the wrong order, so the phone's own attempts to reconnect
were refused.

**The fix** is a small change to one file of the desktop program. You rebuild the
program with the change and run that copy instead. This download is only that change —
no ready-made program comes with it — so you (or Claude) have to build it, which is the
"Information for nerds" part below.

![The patch: one file, one changed handshake](docs/screenshot.jpg)

*The whole fix. You apply it to the KDE Connect source and rebuild.*

## Please test before relying on it

This is shared as-is, with no warranty. It works on my own computers, but your system,
settings and software versions may differ, so please try it in a safe setting first.
If something doesn't work, you can ask Claude (or another AI coding assistant) to look
into it, and I'd appreciate hearing what you found and how you fixed it. You are also
welcome to just let me know at support@veered.org, and I'll look into it.

## License

**This patch is GPL-3.0**, because they are derivative of cosmic-utils/kdeconnect,
which is licensed GPL-3.0 (per the GitHub API and the repository `LICENSE` file). The


## Information for nerds

### The bug

Tested against upstream commit `c83895fc1dde8073184df471b669ad2b999e31d1`
(flatpak release 0.10.0), of the COSMIC KDE Connect daemon
([cosmic-utils/kdeconnect](https://github.com/cosmic-utils/kdeconnect), also shipped as
the flatpak `io.github.hepp3n.kdeconnect`). No binaries and no source tree are
distributed here, only the patch.

`kdeconnect-core/src/transport.rs::complete_handshake()` always upgraded the socket
to TLS as the **server**, on both connection paths. The KDE Connect protocol ties the
TLS role to who opened the TCP socket: the side that initiated the connection is the
TLS server, and the side that accepted it is the TLS client.

| Discovery                 | Who dials TCP   | Desktop TLS role (before) | Result |
|---------------------------|-----------------|---------------------------|--------|
| phone broadcasts UDP      | desktop         | server (correct)          | works  |
| desktop broadcasts UDP    | phone           | server (should be client) | `TLS accept failed: tls handshake eof` |

Android only broadcasts when the KDE Connect app is opened or refreshed, so once the
link drops it only comes back when you open the app on the phone.

### The fix

`complete_handshake()` gains a `TlsRole` parameter. On the TCP accept path the daemon
now takes the client role (`TlsConnector`) and skips the plaintext identity send, since
the peer's identity has already been read from the socket. The UDP discovery path keeps
the server role. After the change the phone's own unprompted inbound connections
complete and notification packets flow.

### Files

`tls-role-fix.patch` contains only the TLS-role fix (`transport.rs`).

### Building

```sh
sudo apt install build-essential cmake pkg-config libdbus-1-dev libpulse-dev
# Rust via rustup: https://rustup.rs

git clone https://github.com/cosmic-utils/kdeconnect.git
cd kdeconnect
git checkout c83895fc1dde8073184df471b669ad2b999e31d1
git apply /path/to/tls-role-fix.patch
cargo build --release -p kdeconnect-service
install -m755 target/release/kdeconnect-service ~/.local/bin/kdeconnect-service-patched
```

Newer upstream commits may already contain a fix or may need the patch rebased;
`git apply --check` tells you before anything changes.

### Running it alongside the flatpak

1. Start the patched daemon at login, e.g. `~/.config/autostart/kdeconnect-service-patched.desktop`:

   ```ini
   [Desktop Entry]
   Type=Application
   Name=KDE Connect daemon (patched)
   Exec=%h/.local/bin/kdeconnect-service-patched
   X-GNOME-Autostart-enabled=true
   ```

   (Some autostart implementations do not expand `%h`; use an absolute path if so.)

2. The flatpak applet can still autostart for its tray icon; its bundled (unpatched)
   daemon exits on the single-instance guard when the patched one is already running.
   Start the patched daemon first.
3. If the distribution's KDE `kdeconnectd` is also installed, disable its autostart so it
   does not take UDP/TCP port 1716.
4. Pairing state lives in `~/.config/kdeconnect/`.

Troubleshooting: if notifications stop, check the device shows as connected before
anything else. A flatpak update replaces only the flatpak copy; the patched binary in
`~/.local/bin` is untouched.


----- For Claude Code users -----

Download https://veered.org/kdeconnect-cosmic-fix/scarlet-kdeconnect-fix.zip, unzip it into a new folder, read every README.md in it, and help me install and set up "Scarlet" (A KDE Connect fix so your phone's link to COSMIC recovers by itself) on this machine. Check the requirements against this system first and tell me what is missing. Ask me before running anything with sudo, installing packages, or changing existing configuration files, and back those files up first. Finish by showing me how to test it and how to uninstall it.