feat: implement modal keybindings for layout and master pane control

Add XMonad.Hooks.Modal to separate layout switching and master pane
manipulation into distinct modal namespaces. This resolves keybinding
conflicts and creates a more organized interaction model.

Changes:
- Layout mode (M-a l): one-shot layout selection (d/m/f)
- Master mode (M-a m): persistent pane adjustments with arrow keys
- Restore ppExtras with logMode to display active mode in xmobar
- Remove conflicting Home/End/PageUp/PageDown bindings from master pane
- Simplify navigation by moving screen focus back to Home/End

src/xmonad.hs

@@ -6,6 +6,7 @@ import XMonad.Actions.RotSlaves
 import XMonad.Hooks.DynamicLog
 import XMonad.Hooks.EwmhDesktops
 import XMonad.Hooks.ManageDocks
+import XMonad.Hooks.Modal
 import XMonad.Hooks.StatusBar
 import XMonad.Layout.NoBorders
 import XMonad.Layout.Renamed
@@ -30,6 +31,7 @@ main = xmonad
      . ewmhFullscreen
      . ewmh
      . withSB myXmobar
+     . modal [layoutMode, masterMode]
      $ myConfig
 
 myConfig = def
@@ -74,10 +76,9 @@ myKeymap =
     , ("M-a t", spawn myFileManager)
     , ("M-a s", spawn myScrot      )
 
-    -- toggling layouts
-    , ("M-a d", sendMessage $ JumpToLayout "dynamic tiling")
-    , ("M-a m", sendMessage $ JumpToLayout "maximised"     )
-    , ("M-a f", sendMessage $ JumpToLayout "fullscreen"    )
+    -- modal modes
+    , ("M-a l", setMode "layout")
+    , ("M-a m", setMode "master")
 
     -- quit window
     , ("M-a q", kill)
@@ -96,12 +97,12 @@ myKeymap =
     , ("M-<Right>", moveTo Next hiddenWS)
 
     -- window rotation
-    , ("M-S-<Up>",   rotAllUp)
-    , ("M-S-<Down>", rotAllDown)
+    , ("M-<Page_Up>"  , rotAllUp)
+    , ("M-<Page_Down>", rotAllDown)
 
     -- focus screens
-    , ("M-S-<Left>",  prevScreen)
-    , ("M-S-<Right>", nextScreen)
+    , ("M-<Home>", prevScreen)
+    , ("M-<End>" , nextScreen)
 
     -- switch workspaces
     , ("M-1", windows $ W.greedyView "code" )
@@ -117,12 +118,6 @@ myKeymap =
     , ("M-S-4", windows $ W.shift "games")
     , ("M-S-5", windows $ W.shift "misc" )
 
-    -- master pane manipulation
-    , ("M-<Home>",      sendMessage Shrink)            -- shrink master pane width
-    , ("M-<End>",       sendMessage Expand)            -- expand master pane width
-    , ("M-<Page_Up>",   sendMessage (IncMasterN 1))    -- more windows in master
-    , ("M-<Page_Down>", sendMessage (IncMasterN (-1))) -- fewer windows in master
-
     -- master window operations
     , ("M-<Delete>",   windows W.focusMaster)
     , ("M-S-<Delete>", windows W.swapMaster )
@@ -141,6 +136,26 @@ myKeymap =
     ]
 
 
+--
+-- Modal Modes
+--
+
+layoutMode :: Mode
+layoutMode = mode "layout" $ mkKeysEz
+    [ ("d", sendMessage (JumpToLayout "dynamic tiling"))
+    , ("m", sendMessage (JumpToLayout "maximised"     ))
+    , ("f", sendMessage (JumpToLayout "fullscreen"    ))
+    ]
+
+masterMode :: Mode
+masterMode = modeWithExit "master" $ mkKeysEz
+    [ ("<Left>",  sendMessage Shrink)
+    , ("<Right>", sendMessage Expand)
+    , ("<Up>",    sendMessage (IncMasterN 1))
+    , ("<Down>",  sendMessage (IncMasterN (-1)))
+    ]
+
+
 --
 -- Layouts
 --
@@ -175,8 +190,11 @@ myXmobarPP = def
     , ppHiddenNoWindows = grey0  . wrap " " ""
     , ppUrgent          = red    . wrap " " ""
     , ppLayout          = aqua   . wrap (grey0 " <fn=1>[</fn> ") (grey0 " <fn=1>]</fn> ")
-    , ppOrder           = \[ws, l, _] -> [ws, l]
+    , ppOrder           = \case { [ws, l, title, mode] -> [ws, l, mode, title]; xs -> xs }
+    , ppExtras          = [lMode]
     }
+  where
+    lMode = xmobarColorL "#d8a657" "#282828" . fixedWidthL AlignCenter "-" 4 $ logMode
 
 
 --