Add mouse window controls and finer display scaling (#63)

Add configurable mouse and wheel bindings, window move and resize, tab drops, cross-output dragging, and device settings. Adjust display scaling in 0.05 increments.

Preserve opposite-edge positioning during scrolling resizes and show rows for edge drops into tabbed columns.

docs/configuration/input.md

@@ -19,9 +19,43 @@ focus keys move the selection, Enter activates it, and Escape dismisses Overview
 Clicking a workspace card's background switches workspaces while keeping Overview
 open. Previews follow layout order and use the configured shell font and colors.
 
-The touchpad device keys are booleans, all defaulting to `true`: `tap`,
-`natural-scroll` and `disable-while-typing`. These apply to DRM devices; nested
-previews use the host's physical input settings.
+The touchpad keys `tap`, `natural-scroll` and `disable-while-typing` default to
+`true`. Set `disable-while-mouse-connected #true` to pause a built-in touchpad
+while an external mouse is connected. It defaults to `false` and uses libinput's
+external-mouse policy on supported touchpads, including when a mouse is plugged
+in or removed during the session. The toggle is also in **Settings → Keyboard & mouse**.
+These device settings apply to DRM sessions; nested previews use the host's
+physical input settings.
+
+Touchpad `accel-speed` is independent of the mouse setting. It accepts −1.0 to
+1.0 and defaults to 0.0. Both speed controls are available in Settings and reload
+immediately in a hardware session.
+
+```kdl
+input {
+    touchpad {
+        accel-speed 0.0
+        disable-while-mouse-connected #true
+    }
+    mouse {
+        natural-scroll #false
+        accel-speed 0.0
+        // accel-profile "flat"
+        left-handed #false
+        middle-emulation #false
+        scroll-factor 1.0
+        drag-threshold 4.0
+        scroll-cooldown-ms 150
+    }
+}
+```
+
+Mouse settings are separate from touchpad settings and reload live. `accel-speed`
+accepts -1.0 to 1.0; `accel-profile` accepts `adaptive` or `flat`, and follows the
+device default when omitted. `scroll-factor` scales application wheel scrolling
+(0.01–100). `drag-threshold` is the distance before a window drag starts (0–100
+logical pixels). `scroll-cooldown-ms` limits repeated wheel bindings (0–5000 ms);
+zero allows each accumulated tick to run its action.
 
 Workspace swipes and left/right window-focus swipes follow your fingers and settle
 when released. Up goes to the next workspace on the
@@ -51,3 +85,38 @@ hardware session.
 
 Adjust recognition distance in **Settings → Keyboard & mouse**, or with
 `swipe-threshold 80` under `input.touchpad` (integer 16–1000 logical pixels).
+
+## Mouse bindings
+
+`Super+MouseLeft` drags a window and `Super+MouseRight` resizes it. Both work with
+floating windows and tiled windows in scrolling or tree layouts. Drag a tiled
+window to another window's edge to place it beside that window, or to its center
+to join a tab group. Top and bottom drops into a tabbed column show its windows as
+rows. Drag across monitors to move to the workspace shown there.
+While dragging, right-click to switch between floating and tiling. Scroll or hold
+the pointer at a horizontal screen edge to reach other scrolling columns.
+Escape cancels the operation; releasing the initiating button finishes it.
+Fullscreen windows keep their current layout until you leave fullscreen.
+
+Mouse bindings use the same actions, overrides and named binding modes as keyboard
+bindings. Ordinary actions use the current keyboard focus; `pointer-move` and
+`pointer-resize` operate on the window under the pointer. Client popup grabs,
+pointer constraints, shortcut inhibition and session locking take precedence.
+
+```kdl
+binding "Alt+MouseLeft" action="pointer-move"
+binding "Alt+MouseRight" action="pointer-resize"
+binding "Super+MouseLeft" disabled=#true
+binding "Super+WheelUp" action="workspace-previous"
+binding "Super+WheelDown" action="workspace-next"
+binding "Super+TouchpadScrollLeft" action="focus" argument="left"
+binding "Super+MouseBack" action="focus-last-window"
+```
+
+Buttons include `MouseLeft`, `MouseRight`, `MouseMiddle`, `MouseBack` and
+`MouseForward`, or `mouse:272` through `mouse:287` for Linux mouse button codes.
+Wheel directions are `WheelUp`, `WheelDown`, `WheelLeft` and `WheelRight`.
+Touchpad scroll bindings use the `TouchpadScroll` prefix with the same directions.
+Only a bound scroll axis is intercepted; the other axis still reaches the client.
+High-resolution wheel steps accumulate into ticks. An intercepted touchpad scroll
+keeps its event ownership until the gesture stops, even if modifiers change.