Add freehand exclusion mode

Support rectangle and freehand exclusion shapes, toggle via toolbar, and store new strokes in the mask-backed exclusion system.

app/lang/de.toml

@@ -6,11 +6,14 @@
 "toolbar.pick_from_image" = "Farbe aus Bild klicken"
 "toolbar.save_overlay" = "Overlay speichern"
 "toolbar.clear_excludes" = "Ausschlüsse löschen"
+"toolbar.toggle_free_draw" = "Freihandmodus umschalten"
 "toolbar.undo_exclude" = "Letzten Ausschluss entfernen"
 "toolbar.reset_sliders" = "Slider zurücksetzen"
 "toolbar.toggle_theme" = "Theme umschalten"
 "status.no_file" = "Keine Datei geladen."
 "status.defaults_restored" = "Standardwerte aktiv."
+"status.free_draw_enabled" = "Freihand-Ausschluss aktiviert."
+"status.free_draw_disabled" = "Rechteck-Ausschluss aktiviert."
 "status.loaded" = "Geladen: {name} — {dimensions}{position}"
 "status.filename_label" = "{name} — {dimensions}{position}"
 "status.color_selected" = "Farbe gewählt: {label} — Hue {hue:.1f}°, S {saturation:.0f}%, V {value:.0f}%"

app/lang/en.toml

@@ -6,11 +6,14 @@
 "toolbar.pick_from_image" = "Pick from image"
 "toolbar.save_overlay" = "Save overlay"
 "toolbar.clear_excludes" = "Clear exclusions"
+"toolbar.toggle_free_draw" = "Toggle free-draw"
 "toolbar.undo_exclude" = "Undo last exclusion"
 "toolbar.reset_sliders" = "Reset sliders"
 "toolbar.toggle_theme" = "Toggle theme"
 "status.no_file" = "No file loaded."
 "status.defaults_restored" = "Defaults restored."
+"status.free_draw_enabled" = "Free-draw exclusion mode enabled."
+"status.free_draw_disabled" = "Rectangle exclusion mode enabled."
 "status.loaded" = "Loaded: {name} — {dimensions}{position}"
 "status.filename_label" = "{name} — {dimensions}{position}"
 "status.color_selected" = "Colour chosen: {label} — Hue {hue:.1f}°, S {saturation:.0f}%, V {value:.0f}%"