Build the eight asks recovered from the previous session's transcript

The punch list was not the whole record. These are the owner's own typed
requests, read back out of the previous session's transcript rather than
guessed at, then each checked against the code before being treated as open.
Three they suspected were already done really were: dialogs already had a
Close-only titlebar, inactive dimming already existed, and the corner resize
hitbox had already been tuned.

Snap layouts on drag, asked for twice. Edge snapping worked but committed
silently on release with nothing shown first, so there was no way to know it
would happen or where. A translucent drop-target preview now follows the
drag, and throwing the pointer at a monitor's top edge drops down the
existing six-cell grid to aim at. The preview calls the same snap_zone that
end_drag does, so the two cannot disagree. Two defects found by screenshot
before landing: moving down onto the flyout closed it, and its labels
overflowed at a fixed cell width - the same "text goes out of view" fault
already fixed once for the context menu.

New File now offers real types, chosen by extension, with the de-duplication
counter placed before the extension so the file stays what it says it is.

Refresh re-reads init.lua and fires a new srd.on("refresh") handler instead
of only re-scanning the icon grid. What refresh means beyond srdwm's own
config stays the config's decision.

general.config_reload_on_write (default on) applies an edited config on save,
via an mtime sweep rather than an inotify watch: no new dependency, same
behaviour on every target, and unaffected by editors that write through a
temp file.

A real bug behind "what happens when our config fails": you lost every
keybinding. do_reload cleared the binding, handler and repeat tables before
re-executing and never restored them, so a syntax error left neither the old
config nor the new one, and the only key still working was the reload combo
nobody thinks to press. The tables are now restored on any failure and
config errors reach notify-send, not just the log.

srd.lock() and a default Mod4+Ctrl+l binding: the built-in lock screen could
not be reached from Lua at all. Native rather than shelling out, because a
lock key that shells out fails silently when the binary is not on PATH.
Default bindings added for srd.window.move and a dynamic/tiling toggle, both
of which existed with no way to reach them, plus srd.layout.get() so the
toggle reads the live workspace rather than the configured default.

Dialogs open centred, and are excluded from remembered geometry in both
directions - that table is keyed by app_id, which a dialog shares with the
window that spawned it, so dialogs inherited an unrelated position and size
and then overwrote it with their own.

theme.decorations.title_bar.button_mode (dynamic by default, or fixed) drops
the Maximize button on a window whose client pinned min == max size, where
pressing it can do nothing. Maximize is removed from the slot list rather
than skipped in place on both the render and hit-test sides, so the remaining
buttons close the gap identically; three tests pin that agreement, which is
what fails silently when it drifts.

Also: the nested backend's screencopy pass now draws both menus, the flyout
and the drag preview. Four investigations in one day started from a
screenshot missing a tier, so that pass carries an explicit list of what it
still omits and the on-screen loop points at it.

512 tests pass, clippy clean.

1 files changed, 57 insertions, 0 deletions

diff --git a/crates/wayland/src/elements.rs b/crates/wayland/src/elements.rs
index b5be5a8..1fafcae 100644
--- a/crates/wayland/src/elements.rs
+++ b/crates/wayland/src/elements.rs
@@ -77,6 +77,63 @@ pub(crate) fn border_side_render_element(buf: &mut SolidColorBuffer, strip: srdw
     SolidColorRenderElement::from_buffer(buf, loc, 1.0, 1.0, Kind::Unspecified)
 }
 
+/// How thick the snap preview's outline is, in logical pixels.
+const SNAP_PREVIEW_OUTLINE: i32 = 3;
+
+/// Opacity of the snap preview's translucent interior fill.
+///
+/// Low on purpose: this sits on top of whatever is already on screen, and
+/// its job is to say "the window lands *here*" without hiding what is
+/// underneath. The outline carries the shape; the fill only tints it.
+const SNAP_PREVIEW_FILL_ALPHA: f32 = 0.22;
+
+/// The drop-target overlay drawn while a window is being dragged into a
+/// snap zone - a translucent fill plus a solid outline over the rect the
+/// window will occupy when the button comes up.
+///
+/// `buffers` is a persistent pool (five entries: fill, then top/bottom/
+/// left/right outline) for exactly the reason [`border_side_render_element`]
+/// documents at length - a fresh `SolidColorBuffer` per frame gets a fresh
+/// `Id`, which makes smithay's damage tracker mark the element damaged on
+/// every frame forever and stops the output ever going idle.
+///
+/// Solid fills, not a rasterised bitmap: the preview rect is up to a whole
+/// monitor in size and changes as the drag moves, so building an ARGB
+/// buffer for it would mean allocating and filling megabytes per zone
+/// change. `Frame::draw_solid` needs no texture at all.
+pub(crate) fn snap_preview_elements(buffers: &mut Vec<SolidColorBuffer>, rect: srdwm_core::Rect, color: (u8, u8, u8), origin: (i32, i32)) -> Vec<SolidColorRenderElement> {
+    if rect.width == 0 || rect.height == 0 {
+        return Vec::new();
+    }
+    let (r, g, b) = (color.0 as f32 / 255.0, color.1 as f32 / 255.0, color.2 as f32 / 255.0);
+    let t = SNAP_PREVIEW_OUTLINE.min(rect.width as i32 / 2).min(rect.height as i32 / 2).max(1);
+    let (w, h) = (rect.width as i32, rect.height as i32);
+    // Fill first so the outline draws over it, then the four edges.
+    let parts: [(srdwm_core::Rect, f32); 5] = [
+        (rect, SNAP_PREVIEW_FILL_ALPHA),
+        (srdwm_core::Rect::new(rect.x, rect.y, rect.width, t as u32), 1.0),
+        (srdwm_core::Rect::new(rect.x, rect.y + h - t, rect.width, t as u32), 1.0),
+        (srdwm_core::Rect::new(rect.x, rect.y + t, t as u32, (h - 2 * t).max(0) as u32), 1.0),
+        (srdwm_core::Rect::new(rect.x + w - t, rect.y + t, t as u32, (h - 2 * t).max(0) as u32), 1.0),
+    ];
+    let mut out = Vec::with_capacity(parts.len());
+    for (index, (part, alpha)) in parts.into_iter().enumerate() {
+        if part.width == 0 || part.height == 0 {
+            continue;
+        }
+        let buf = border_fragment_buffer(buffers, index);
+        // Alpha lives in the element, not the buffer colour: `SolidColorBuffer::
+        // update` only bumps its commit counter when size or colour change,
+        // so keeping the colour opaque here means a preview that merely
+        // moves does not also invalidate on a colour it never actually
+        // changed.
+        buf.update((part.width as i32, part.height as i32), Color32F::new(r, g, b, 1.0));
+        let loc = Point::from((part.x - origin.0, part.y - origin.1));
+        out.push(SolidColorRenderElement::from_buffer(buf, loc, 1.0, alpha, Kind::Unspecified));
+    }
+    out
+}
+
 /// Splits a border strip into the sub-rectangles still visible after
 /// subtracting every window rect stacked in front of it.
 ///