hypr: make the per-host config lookup case-insensitive

The hosts files were written capitalized (Rutherford.lua, Chester.lua)
but the require uses the hostname exactly as `hostname` prints it —
lowercase — so on a case-sensitive filesystem the lookup missed and
pcall silently swallowed it. The per-host monitor overrides therefore
never loaded on either machine. Normalize the hostname to lowercase
and name the files in lowercase so any casing matches.

hypr/hosts/chester.lua

@@ -0,0 +1,11 @@
+-- Host-specific overrides: Chester (laptop, 2880x1800 internal display)
+-- Loaded automatically by hyprland.lua via hostname detection.
+-- Keeps the internal panel at 1.5x scaling (virtual 1920x1200).
+
+-- Laptop internal display — explicit & stable
+hl.monitor({
+    output   = "eDP-1",
+    mode     = "2880x1800@60",
+    position = "0x0",
+    scale    = 1.5,
+})