initial commit

_bmad-output/implementation-artifacts/9-3-pwa-support.md

@@ -0,0 +1,37 @@
+---
+epic: 9
+story: 9.3
+title: "PWA Support"
+status: draft
+---
+
+## Epic 9 — Web App (React + WASM)
+**Goal:** Zero-install web experience with real-time collaboration.
+
+### Story 9.3: PWA Support
+
+As a web user,
+I want CalcPad to work offline and be installable on my device,
+So that I can use it like a native app without network dependency.
+
+**Acceptance Criteria:**
+
+**Given** the web app has been visited at least once
+**When** the user loses network connectivity
+**Then** the service worker serves the cached application shell and assets
+**And** all previously loaded sheets remain accessible and editable offline
+
+**Given** a user visits the web app in a supported browser
+**When** the browser detects the PWA manifest
+**Then** an "Add to Home Screen" / install prompt is available
+**And** installing creates a standalone app icon on the user's device
+
+**Given** the app is running offline
+**When** a user performs a currency or unit conversion that relies on exchange rates
+**Then** the most recently cached rates are used for evaluation
+**And** a subtle indicator shows that rates may be stale
+
+**Given** a user navigates to the web app for the first time on a reasonable connection
+**When** the initial page load completes
+**Then** the time to interactive is less than 2 seconds
+**And** the app scores above 90 on Lighthouse PWA, Performance, and Best Practices audits