feat(home): add satty for screenshot annotation

Added satty (Wayland-native screenshot annotation tool) and integrated it with the Capture flow.
Wired `$mod SHIFT, Print` to slurp a region and open satty.
Added "Annotate region" to the rofi Capture menu (Tools > Capture).
Added satty's configuration via home-manager to inject the active theme's palette colors into its UI.

Verified: V1 (flake check --no-build, home activation package build).
Pending: V3 hardware/visual check for the satty UI (queued in HARDWARE-QUEUE.md).

modules/home/rofi.nix

@@ -460,6 +460,7 @@ ${themeRows}
         choice=$( {
           row "Region → clipboard${hintForBind "" "Print"}" applets-screenshooter
           row "Region → file${hintForBind "SHIFT" "Print"}" applets-screenshooter
+          command -v satty >/dev/null 2>&1 && row "Annotate region${hintForBind "$mod SHIFT" "Print"}" edit-image
           row "Full screen → clipboard" camera-photo
           row "Full screen → file${hintForBind "CTRL" "Print"}" camera-photo
           command -v tesseract >/dev/null 2>&1 && row "OCR region → clipboard" scanner
@@ -482,6 +483,7 @@ ${themeRows}
           *"Region → clipboard"*)      grim -g "$(slurp)" - | wl-copy ;;
           *"Region → file"*)           mkdir -p "$dir"; grim -g "$(slurp)" "$file" \
                                          && notify-send "Screenshot saved" "$file" ;;
+          *"Annotate region"*)         mkdir -p "$dir"; grim -g "$(slurp)" - | satty --filename - --fullscreen --output-filename "$file" ;;
           *"OCR region"*)
             # Select → screenshot → tesseract → clipboard. Esc in slurp
             # cancels silently (the recording.nix pattern); recognizing