Popup auf SNI-Desktops: Activate-Koordinaten (Anchor::Click) + Cinnamon-Extension

- SNI-Activate-Koordinaten gehen als Anchor::Click durch; Cinnamon liefert
  echte Werte, bei (0,0) bleibt der Cursor-Fallback (KDE/XFCE).
- Neue Cinnamon-Extension ai-control-popup@local: platziert das Popup unter
  Wayland am Zeiger (Work-Area-geklemmt, set_position ist dort wirkungslos)
  und gibt ihm unter X11 den initialen Fokus (Muffins Focus-Stealing-
  Prevention verwirft das present() der App).
- Extension in deb/rpm nach /usr/share/cinnamon/extensions paketiert.
- README: Cinnamon-Abschnitte und Installer-Teststand aktualisiert.

Verifiziert in der VM-Flotte: Cinnamon Wayland + X11, XFCE, KDE (Wayland),
GNOME (Wayland).

README.md

@@ -64,11 +64,11 @@ Releases carry a `.deb`, an `.rpm`, and an AppImage.
 - **deb / rpm** — recommended. Both also install the GNOME Shell extension and the KWin script that provide the tray/popup integration on GNOME and KDE Wayland (into `/usr/share/gnome-shell/extensions/` and `/usr/share/kwin/scripts/`).
 - **AppImage** — runs on desktops with a standard tray (KDE, XFCE, Cinnamon). On GNOME it refuses to start and points to the deb/rpm: the tray there needs the shell extension, which an installation-free AppImage cannot provide.
 
-Tray integration by desktop: GNOME via the bundled shell extension, KDE Wayland via StatusNotifierItem plus the bundled KWin script for popup placement, KDE X11/XFCE/Cinnamon via StatusNotifierItem directly.
+Tray integration by desktop: GNOME via the bundled shell extension, KDE Wayland via StatusNotifierItem plus the bundled KWin script for popup placement, KDE X11/XFCE/Cinnamon via StatusNotifierItem directly. On Cinnamon **Wayland** sessions a bundled Cinnamon extension additionally places the popup at the tray icon (a Wayland client cannot position its own window); Cinnamon X11 needs no extension.
 
 ### Installer tests
 
-The installers are hand-tested per release. Current state: Fedora 44 via rpm on GNOME, KDE Plasma, Cinnamon, and XFCE (VM test fleet); Ubuntu 26.04 (GNOME), Kubuntu (KDE Plasma, Wayland) and Linux Mint (Cinnamon) via deb in earlier rounds. Two known issues from the current round are open: on Cinnamon the tray popup opens at the top-left corner instead of at the tray icon, and on the X11 desktops (Cinnamon, XFCE) clicking outside the popup does not close it. macOS re-test of the current build is in progress.
+The installers are hand-tested per release. Current state: Fedora 44 via rpm on GNOME, KDE Plasma, Cinnamon, and XFCE (VM test fleet); Ubuntu 26.04 (GNOME), Kubuntu (KDE Plasma, Wayland) and Linux Mint (Cinnamon) via deb in earlier rounds. The two open findings from that round are resolved: popup placement on Cinnamon Wayland now comes from the bundled Cinnamon extension, and click-outside-to-close verified fine on XFCE and Cinnamon. macOS re-test of the current build is in progress.
 
 ### Windows
 
@@ -109,6 +109,7 @@ Deleting a project is scoped in three stages, each preceded by a preview of the
 │   ├── capabilities/     per-window ACL (main/popup/terminal/panel)
 │   └── icons/            app and tray icons
 ├── gnome-shell-extension/  tray/popup integration for GNOME
+├── cinnamon-extension/     popup placement for Cinnamon Wayland
 ├── kwin-script/            popup placement for KDE Wayland
 ├── dev.sh                development mode (tauri dev)
 ├── build.sh              release build for the current OS (see below)