fix(ux): prevent iOS auto-zoom on inputs + lazy-load page CSS

Increase font-size to 16px on mobile for shopping quick-add inputs,
notes search, and contacts search. Desktop breakpoint restores compact
sizes. Move 9 page-specific stylesheets from index.html to on-demand
loading in router.js, reducing initial CSS payload.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "oikos",
-  "version": "0.7.2",
+  "version": "0.7.3",
   "description": "Self-hosted family planner - calendar, tasks, shopping, meal planning, budget and more. Private, open-source, no subscription.",
   "main": "server/index.js",
   "type": "module",