chore: cleanup for push to main

- Remove CLAUDE.md, TODO.md (dev-only task trackers)
- Remove umutray.service (unused systemd unit)
- Remove .vscode/settings.json (stale Makefile ref)
- Add src/theme.rs (shared palette/styling module)
- Update .gitignore: exclude .vscode/, packaging build artifacts
- Fix README: add gui command, correct service description
- Delete ~1.3GB packaging build artifacts from working tree

Code changes from prior session (already committed locally):
- Tray icon launches alongside GUI, close dialog with minimize-to-tray
- Theme module extraction, button shadow fixes, UI polish
- Game detection filtering, prettify_game_name, Battle.net fix

README.md

@@ -28,7 +28,7 @@ Launch / Kill entries. Users can add or remove launchers in `config edit`.
   (no ~600 MB in-memory buffering), with a progress indicator.
 - `diagnose` — sanity-checks umu-run, Vulkan, display server, per-launcher
   prefix / exe / ownership / running state.
-- `service` — installs a `systemd --user` unit so the tray autostarts with
+- `service` — installs an XDG autostart entry so the tray autostarts with
   the graphical session.
 - `setup` — graphical wizard (iced) that downloads an installer URL
   (with progress bar) or accepts a local `.exe`, then runs it via
@@ -59,6 +59,7 @@ umutray service install
 | Command                          | What it does                                            |
 | -------------------------------- | ------------------------------------------------------- |
 | `umutray`                        | Start the tray daemon (default)                         |
+| `umutray gui`                    | Open the graphical dashboard (with tray icon)           |
 | `umutray launchers`              | List configured launchers and their state               |
 | `umutray launch <name>`          | Launch a specific launcher (e.g. `umutray launch epic`) |
 | `umutray kill [<name>]`          | Kill one launcher, or all if no name is given           |
@@ -78,9 +79,9 @@ umutray service install
 | `umutray config add-game …`      | Attach a game to a launcher (needs `--exe-path`)        |
 | `umutray config remove-game …`   | Drop a game from a launcher                             |
 | `umutray config set-game-flags …`| Per-game overlay toggles: gamemode/mangohud/gamescope   |
-| `umutray service install`        | Write + enable a `systemd --user` unit                  |
-| `umutray service uninstall`      | Stop, disable, and remove the unit                      |
-| `umutray service status`         | `systemctl --user status umutray.service`               |
+| `umutray service install`        | Write XDG autostart entry (tray starts on login)        |
+| `umutray service uninstall`      | Remove the autostart and desktop entries                |
+| `umutray service status`         | Show whether XDG autostart is enabled                   |
 
 ## Config