fix(render): camera clamp keeps the far edge on the map; drop unused pan

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

crates/cyberpunk/src/render/viewport.rs

@@ -32,11 +32,6 @@ impl Camera {
         self.ty = p.y;
     }
 
-    pub fn pan(&mut self, dx: i32, dy: i32) {
-        self.tx += dx;
-        self.ty += dy;
-    }
-
     /// Moves the target only when `p` leaves the middle third of the view.
     pub fn follow(&mut self, p: Pos, view_w: u16, view_h: u16) {
         let zx = (view_w as i32 / 6).max(1);
@@ -71,13 +66,14 @@ impl Camera {
         let half_h = view_h as i32 / 2;
         let w = size.w as i32;
         let h = size.h as i32;
+        // The view spans origin..origin+view, so the far bound is the view's other half.
         self.tx = if w > view_w as i32 {
-            self.tx.clamp(half_w, w - half_w)
+            self.tx.clamp(half_w, w - (view_w as i32 - half_w))
         } else {
             w / 2
         };
         self.ty = if h > view_h as i32 {
-            self.ty.clamp(half_h, h - half_h)
+            self.ty.clamp(half_h, h - (view_h as i32 - half_h))
         } else {
             h / 2
         };

crates/cyberpunk/src/screens/explore.rs

@@ -554,6 +554,7 @@ mod tests {
         let mut s = MapScreen::explore(0);
         let mut t = Terminal::new(TestBackend::new(120, 40)).unwrap();
         t.draw(|f| s.draw(&st, f)).unwrap();
+        s.update(&mut st, &[]);
         let before = s.cursor;
         s.update(&mut st, &[key(KeyCode::Right), key(KeyCode::Down)]);
         assert_eq!(s.cursor, Pos::new(before.x + 1, before.y + 1));