fix: Multiple ADHD/Focus Tools fixes

Switch/Checkbox Styling:
- Exclude switches and checkboxes from larger-targets CSS
- Fix checkbox square aspect ratio when ADHD mode enabled
- Prevent padding from being applied to form controls

Quick Wins Count:
- Use settings.quickWinThreshold instead of hardcoded 15
- Match same filtering logic as QuickWinList component

Back Button Navigation:
- Use window.history.back() instead of setLocation('/')
- Works correctly when navigating from ADHD dashboard to sub-pages

Time Tracking (Break Reminder):
- Track only active browser time using Page Visibility API
- Reset accumulated time after 8 hours of inactivity
- Store/restore active time in localStorage properly
- No more 1500+ hour counts from leaving browser open

Sources:
- https://ui.shadcn.com/docs/theming (shadcn theming)
- https://ui.shadcn.com/docs/tailwind-v4 (Tailwind v4 updates)

client/src/index.css

@@ -380,22 +380,23 @@
 
 /* Larger Touch Targets for ADHD Mode */
 /* Only increase height, not width - width breaks flex layouts and icon buttons */
-.larger-targets button:not([data-size="icon"]),
-.larger-targets [role="button"]:not([data-size="icon"]) {
+/* Exclude switches, checkboxes, and sliders from larger targets - they have specific sizing */
+.larger-targets button:not([data-size="icon"]):not([role="switch"]):not([role="checkbox"]),
+.larger-targets [role="button"]:not([data-size="icon"]):not([role="switch"]):not([role="checkbox"]) {
   min-height: 44px;
   padding-top: 0.625rem;
   padding-bottom: 0.625rem;
 }
 
-/* Icon buttons get increased size as square */
-.larger-targets button[data-size="icon"],
-.larger-targets [role="button"][data-size="icon"] {
+/* Icon buttons get increased size as square - but not switches */
+.larger-targets button[data-size="icon"]:not([role="switch"]),
+.larger-targets [role="button"][data-size="icon"]:not([role="switch"]) {
   min-height: 44px;
   min-width: 44px;
 }
 
-/* Form inputs and selects */
-.larger-targets input,
+/* Form inputs and selects - exclude checkbox and switch */
+.larger-targets input:not([type="checkbox"]):not([role="switch"]),
 .larger-targets select,
 .larger-targets textarea {
   min-height: 44px;
@@ -410,6 +411,25 @@
   min-height: 52px;
 }
 
+/* Checkboxes and switches should maintain their aspect ratio */
+.larger-targets [role="switch"],
+.larger-targets [role="checkbox"],
+.larger-targets input[type="checkbox"] {
+  min-height: auto !important;
+  min-width: auto !important;
+  padding-top: 0 !important;
+  padding-bottom: 0 !important;
+}
+
+/* Specific fix for Radix checkbox buttons - ensure square aspect ratio */
+.larger-targets button[role="checkbox"] {
+  height: 1rem !important;
+  width: 1rem !important;
+  min-height: 1rem !important;
+  min-width: 1rem !important;
+  padding: 0 !important;
+}
+
 /* Visual Timer Color Classes */
 .timer-green {
   color: hsl(var(--adhd-timer-green));