tanin-eww skel: disable niri hot corner, bind Overview to Mod+Q

Ports tonight's live config.kdl fixes into the ISO/fresh-install niri
template so new TANINUX installs get them too, not just this machine:
- gestures { hot-corners { off } }: the native top-left hot corner has no
  way to know about a centered multi-monitor layout, so approaching it lets
  the cursor slide onto a neighboring output before the corner reacts — and
  it fired even under fullscreen games. TANINUX already ships its own
  configurable Overview trigger (Settings > Display), so the native corner
  is pure liability with no unique value.
- Mod+Q { toggle-overview; }: this config's binds{} replaces niri's
  defaults wholesale rather than merging, so niri's built-in Mod+O binding
  never actually existed here. Q was free (W is close-window).

packaging/tanin-eww/niri-config.kdl

@@ -1,6 +1,19 @@
 // niri config — ported from the Hyprland/eww setup.
 // Docs: https://niri-wm.github.io/niri/  ·  validate with `niri validate`.
 
+// Native niri hot corner (top-left) deaktiviert: bei einem zentrierten
+// Multi-Monitor-Layout gibt es keinen physischen "Rand", der ein Abrutschen
+// auf den Nachbarschirm verhindert — der Cursor rutscht beim Ansteuern der
+// Ecke auf das links liegende Display, bevor die Ecke selbst reagiert.
+// Zusätzlich reagierte die Ecke ungewollt auch über Fullscreen-Spielen.
+// TANINUX stellt einen eigenen, konfigurierbaren Overview-Trigger bereit
+// (Settings > Display > Overview trigger); Overview per Tastatur ist Mod+Q.
+gestures {
+    hot-corners {
+        off
+    }
+}
+
 input {
     keyboard {
         xkb {
@@ -137,6 +150,11 @@ binds {
     Mod+E         hotkey-overlay-title="Files: nautilus"   { spawn "nautilus"; }
     Mod+Space     hotkey-overlay-title="Apps: Spotlight"   { spawn-sh "$HOME/.config/eww/scripts/spotlight.sh open"; }
     Mod+C         hotkey-overlay-title="Calc: rofi"        { spawn-sh "rofi -show calc"; }
+    // Overview: niri ships this on Mod+O by default, but our binds{} here
+    // REPLACES niri's defaults entirely (not merged) — so Mod+O never
+    // actually exists in this config. Mod+Q was free (Mod+W is
+    // close-window, Hyprland muscle memory), so Overview lives there.
+    Mod+Q repeat=false hotkey-overlay-title="Overview" { toggle-overview; }
 
     // --- eww panels ---
     Mod+A hotkey-overlay-title="Control Center" { spawn-sh "$HOME/.config/eww/scripts/panel.sh toggle control-center"; }