feat: advance login workflow and integration gates

crates/latchd-tui/src/background.rs

@@ -19,6 +19,8 @@ use ratatui::{
 const MAX_IMAGE_SIDE: u32 = 480;
 const MAX_SOURCE_SIDE: u32 = 8_192;
 const MAX_SOURCE_PIXELS: u64 = 16_777_216;
+const MAX_ANIMATION_WIDTH: usize = 160;
+const MAX_ANIMATION_HEIGHT: usize = 64;
 const FRAME_INTERVAL: Duration = Duration::from_millis(120);
 
 /// Background state owned by the TUI thread.
@@ -189,6 +191,10 @@ struct Automata {
 
 impl Automata {
     fn resize(&mut self, width: usize, height: usize) {
+        // Keep procedural state bounded even when a terminal reports an
+        // unusually large window. Rendering remains clipped to this layer.
+        let width = width.min(MAX_ANIMATION_WIDTH);
+        let height = height.min(MAX_ANIMATION_HEIGHT);
         if self.width == width && self.height == height {
             return;
         }
@@ -221,11 +227,11 @@ impl Automata {
         let mut count = 0;
         for dy in [self.height.wrapping_sub(1), 0, 1] {
             for dx in [self.width.wrapping_sub(1), 0, 1] {
-                if dx == 0 && dy == 0 {
-                    continue;
-                }
                 let nx = (x + dx) % self.width;
                 let ny = (y + dy) % self.height;
+                if nx == x && ny == y {
+                    continue;
+                }
                 count += self.current[ny * self.width + nx];
             }
         }
@@ -264,4 +270,16 @@ mod tests {
         automata.tick();
         assert_eq!(automata.current.len(), 32);
     }
+
+    #[test]
+    fn automata_caps_untrusted_terminal_dimensions() {
+        let mut automata = Automata::default();
+        automata.resize(usize::MAX, usize::MAX);
+        assert_eq!(automata.width, MAX_ANIMATION_WIDTH);
+        assert_eq!(automata.height, MAX_ANIMATION_HEIGHT);
+        assert_eq!(
+            automata.current.len(),
+            MAX_ANIMATION_WIDTH * MAX_ANIMATION_HEIGHT
+        );
+    }
 }