clippy: fix dead-code and question-mark warnings

- meta.rs/tour.rs/troubleshoot.rs: annotate content-schema fields that
  real TOML content already populates but no UI reads yet, instead of
  dropping them
- hyprland.rs: drop Monitor's x/y/width/height, genuinely unused
  anywhere and not part of any authored content schema
- tour/mod.rs: collapse a let-else into ? in the Option-returning
  on_tour_event closure

(cherry picked from commit 4497eca4661112f808d33ef477265d39e0e0a601)

src/services/hyprland.rs

@@ -28,10 +28,6 @@ pub struct Client {
 pub struct Monitor {
     pub id: i32,
     pub name: String,
-    pub x: i32,
-    pub y: i32,
-    pub width: i32,
-    pub height: i32,
     pub focused: bool,
 }