feat(display-server): add DisplayServer<F: Framebuffer> with protocol, mock adapter, and tests

crates/servers/display-server/src/adapters/mock.rs

@@ -0,0 +1,66 @@
+use crate::framebuffer::Framebuffer;
+
+pub struct MockFramebuffer {
+    width: u16,
+    height: u16,
+    pixels: [(u16, u16, u32); 4096],
+    pixel_count: usize,
+    flushed: bool,
+}
+
+impl MockFramebuffer {
+    pub fn new(width: u16, height: u16) -> Self {
+        Self {
+            width,
+            height,
+            pixels: [(0, 0, 0); 4096],
+            pixel_count: 0,
+            flushed: false,
+        }
+    }
+
+    pub fn pixel_count(&self) -> usize {
+        self.pixel_count
+    }
+
+    pub fn was_flushed(&self) -> bool {
+        self.flushed
+    }
+
+    pub fn pixel_at(&self, index: usize) -> (u16, u16, u32) {
+        self.pixels[index]
+    }
+}
+
+impl Framebuffer for MockFramebuffer {
+    fn width(&self) -> u16 {
+        self.width
+    }
+
+    fn height(&self) -> u16 {
+        self.height
+    }
+
+    fn write_pixel(&mut self, x: u16, y: u16, color: u32) {
+        if self.pixel_count < self.pixels.len() {
+            self.pixels[self.pixel_count] = (x, y, color);
+            self.pixel_count += 1;
+        }
+    }
+
+    fn fill_rect(&mut self, x: u16, y: u16, w: u16, h: u16, color: u32) {
+        for dy in 0..h {
+            for dx in 0..w {
+                self.write_pixel(x + dx, y + dy, color);
+            }
+        }
+    }
+
+    fn clear(&mut self, _color: u32) {
+        self.pixel_count = 0;
+    }
+
+    fn flush(&mut self) {
+        self.flushed = true;
+    }
+}