Fix the maximize border on the path that actually runs, and three spawn faults

The maximize border was still drawn because the earlier fix landed on the
wrong branch. udev/render.rs has three border blocks: the SRDWM_GPU=1 path
at the top and two Pixman ones below. The patch replaced the first match in
the file, which is the GPU branch a real DRM session never runs. All four
sites across both backends are now gated on !maximized.

The verification had failed twice for a separate reason: winit/capture.rs
did not draw border strips at all, so a screenshot could never answer "is
there a border here" and the control passed for the wrong reason. Border
strips are now drawn into that pass as solid fills - corner rounding is not
reproduced, so a capture is not pixel-exact at the corners, but presence,
position, thickness and colour are. With that closed the test has a real
control: unmaximized gives 6 accent pixels at x=800..805, exactly the
configured border_width, and maximized gives none at the right edge or along
the top row. That proves the winit path; the Pixman path is the same change
at two more sites and is not separately confirmed on screen.

Windows spawning as squares, partly off-screen, and always on the left were
all SmartPlacement::grid. It returned size.min(cell), shrinking every window
to its grid cell whatever size it asked for; it scanned cells in reading
order and took the first free one, which is the leftmost; and nothing clamped
the result, so a window larger than its cell could hang off the edge with its
border out of view. The cell now decides only where a window goes, the scan
starts from a rotating cell, and both grid and cascade clamp into the usable
area. Four tests, one per reported symptom.

525 tests pass, clippy clean.

2 files changed, 28 insertions, 0 deletions

diff --git a/crates/wayland/src/winit/capture.rs b/crates/wayland/src/winit/capture.rs
index 095b56b..3813559 100644
--- a/crates/wayland/src/winit/capture.rs
+++ b/crates/wayland/src/winit/capture.rs
@@ -96,6 +96,7 @@ impl WaylandPlatform {
         // as both on-screen render loops do it.
         let monitor_bounds: Vec<srdwm_core::Rect> = self.wm.borrow().monitors().iter().map(|m| m.full_geometry).collect();
         let mut occluders: Vec<srdwm_core::Rect> = Vec::new();
+        let focused = self.wm.borrow().focused_id();
         for id in self.wm.borrow().visible_windows_front_to_back().map(|w| w.id).collect::<Vec<_>>() {
             let Some(w) = self.wm.borrow().window(id).cloned() else { continue };
             if let Some(deco) = self.state.decorations.get(&id) {
@@ -158,6 +159,32 @@ impl WaylandPlatform {
                     }
                 }
             }
+            // Border strips, as plain solid fills.
+            //
+            // The on-screen loop draws the top and bottom strips from
+            // cached bitmaps so their corners round into the titlebar's
+            // curve, and only the sides as fills. This pass approximates
+            // all four with fills: corner rounding is not reproduced, so a
+            // capture is not pixel-exact at the four corners. Everything
+            // that matters for checking a border - whether one is drawn at
+            // all, where, how thick, and in what colour - is faithful.
+            //
+            // Without this a screenshot could not answer "is there a border
+            // here", which is exactly the question a border bug asks. That
+            // gap was documented and then walked into twice: a maximize
+            // border fix was checked against a capture that never draws
+            // borders, and the control silently passed for the wrong
+            // reason both times.
+            if w.border_width > 0 && !w.maximized {
+                let color = crate::state::effective_border_color(w.border_color, focused == Some(id), self.wm.borrow().theme.border_inactive_dim);
+                let frame = self.state.effective_frame(id, w.geometry);
+                for (index, strip) in crate::decoration::border_strips(frame, w.border_width).into_iter().enumerate() {
+                    for fragment in crate::elements::visible_border_fragments(strip, &occluders) {
+                        let buf = crate::elements::border_fragment_buffer(&mut self.state.capture_border_buffers, index);
+                        custom_elements.push(crate::elements::OverlayElement::Solid(crate::elements::border_side_render_element(buf, fragment, color, (0, 0))));
+                    }
+                }
+            }
             occluders.push(w.geometry);
         }
         custom_elements.extend(crate::elements::output_layer_elements(renderer, &self.output, |layer| matches!(layer, Layer::Background | Layer::Bottom)));
diff --git a/crates/wayland/src/winit/connect.rs b/crates/wayland/src/winit/connect.rs
index 1648826..aa59d9d 100644
--- a/crates/wayland/src/winit/connect.rs
+++ b/crates/wayland/src/winit/connect.rs
@@ -180,6 +180,7 @@ impl WaylandPlatform {
             rounded_content_buffers: HashMap::new(),
             border_side_buffers: HashMap::new(),
             snap_preview_buffers: Vec::new(),
+            capture_border_buffers: Vec::new(),
             color_filter_buffers: HashMap::new(),
             last_synced_size: HashMap::new(),
             provisional_size: HashSet::new(),