Route the Applications page and add its settings

Wires the schema entries and routing the codex agent needs for default
applications, weather, vitals refresh, notification timing, and capture,
so its pages can be written against keys that already exist.

Capture directories and encoder arguments are enums rather than free
text. Both are handed to a recorder process, and a settings page has no
reason to expose an arbitrary string there.

ApplicationsPage.qml is a placeholder so the page id can be routed,
registered, and searchable before the real page lands. It is owned by
the other agent and expected to be replaced wholesale.

Claude-Session: https://claude.ai/code/session_01BRvzt4H8XXLPVH5MyYdk9L

config/dot/quickshell/modules/settings/SettingsSidebar.qml

@@ -30,6 +30,7 @@ Rectangle {
         { page: "accessibility", label: "Accessibility", icon: "\u{F0208}" },
         { page: "power", label: "Power & Lock", icon: "\u{F0425}" },
         { page: "datetime", label: "Date & Time", icon: "\u{F0954}" },
+        { page: "applications", label: "Applications", icon: "\u{F003B}" },
         { page: "services", label: "Startup & Services", icon: "\u{F0493}" },
         { page: "about", label: "About Panama", icon: "\u{F02FD}" }
     ]