feat: "Add to Home Screen" wording + "Get Notified" push dialog

[devin-ai-integration]

Summary

Two copy/layout tweaks to the onboarding prompts:

• Install flow titles renamed from Add ${branding.appName} to your home screen to a plain "Add to Home Screen" (matching iOS's own menu wording): the InstallGuideDialog title and the iOS + Android-fallback toasts in InstallPromptHost. Descriptions, desktop toast, and native-install toast are unchanged.
• PushPromptHost dialog title is now "Get Notified" (was "Get notified about your application status"), and the card is taller and narrower (min-h-72 max-w-xs, flex-col) with full-width stacked buttons — "Allow notifications" on top, "Not now" below.

Link to Devin session: https://app.devin.ai/sessions/3819fb8e090243e3be94e42b6634f587
Open in Devin Desktop: https://app.devin.ai/desktop/session/3819fb8e090243e3be94e42b6634f587?variant=devin
Requested by: @balebbae

[devin-ai-integration]

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