revert: remove dpi detection and configuration for mouse distance feature

This reverts commit df34716ea5, undoing the addition of dpi detection logic and related configuration options for mouse distance calculations.

src/config.c

@@ -61,7 +61,6 @@ void config_set_defaults(Config *cfg)
     cfg->panel_height = DEFAULT_PANEL_HEIGHT;
     cfg->gap = DEFAULT_GAP;
     strncpy(cfg->font_name, "fixed", sizeof(cfg->font_name) - 1);
-    cfg->mouse_distance_dpi = 0.0;
 
     cfg->default_master_ratio = 0.55f;
     cfg->default_master_count = 1;
@@ -159,9 +158,6 @@ static void handle_config_entry(const char *section, const char *key,
             cfg->gap = (val >= 0 && val <= 100) ? val : DEFAULT_GAP;
         } else if (strcmp(key, "font") == 0) {
             strncpy(cfg->font_name, value, sizeof(cfg->font_name) - 1);
-        } else if (strcmp(key, "mouse_distance_dpi") == 0) {
-            double val = atof(value);
-            cfg->mouse_distance_dpi = (val > 0.0) ? val : 0.0;
         }
     } else if (strcmp(section, "layout") == 0) {
         if (strcmp(key, "master_ratio") == 0) {