Fix PWA to open as standalone app instead of browser tab

## manifest.json
- Add `id` and `scope` fields for proper PWA identification
- Split icon purposes into separate entries (was "any maskable", now separate)
- Add `prefer_related_applications: false`

## index.html
- Add `viewport-fit=cover` for notched devices
- Add `mobile-web-app-capable` meta tag
- Add `application-name` and `msapplication` meta tags
- Add both 192px and 512px apple-touch-icon sizes

## styles.css
- Add safe-area-inset padding for notched devices (iPhone X+)
- Use 100dvh for proper mobile viewport height
- Add bottom safe area to toast container and macro grid

## service-worker.js
- Bump cache version to v2 to force update

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

web/css/styles.css

@@ -25,7 +25,12 @@ body {
     background-color: var(--bg-color);
     color: var(--fg-color);
     min-height: 100vh;
+    min-height: 100dvh;
     overflow-x: hidden;
+    /* Safe area for notched devices */
+    padding-top: env(safe-area-inset-top);
+    padding-left: env(safe-area-inset-left);
+    padding-right: env(safe-area-inset-right);
 }
 
 /* Header */
@@ -109,6 +114,7 @@ body {
     grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
     gap: 1rem;
     padding: 1rem;
+    padding-bottom: calc(1rem + env(safe-area-inset-bottom));
 }
 
 .macro-card {
@@ -405,7 +411,7 @@ body {
 /* Status/Toast Messages */
 .toast-container {
     position: fixed;
-    bottom: 1rem;
+    bottom: calc(1rem + env(safe-area-inset-bottom));
     right: 1rem;
     z-index: 300;
 }