Add site plan to frontend project plan

- Mobile-first, desktop first-class citizen
- Navigation: left sidebar (desktop), bottom tabs (mobile)
- 11 routes defined with auth requirements and layouts
- 3 layout types: minimal (login), game (full viewport), default (nav)
- Auth flow: login → starter (if needed) → dashboard
- Dashboard widgets and profile page v1 scope defined

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

frontend/PROJECT_PLAN_FRONTEND.json

@@ -47,6 +47,79 @@
     }
   },
 
+  "sitePlan": {
+    "designApproach": "Mobile-first, desktop is first-class citizen",
+    "navigation": {
+      "desktop": "Left sidebar",
+      "mobile": "Bottom tabs",
+      "items": [
+        {"icon": "home", "label": "Home", "route": "/"},
+        {"icon": "cards", "label": "Collection", "route": "/collection"},
+        {"icon": "deck", "label": "Decks", "route": "/decks"},
+        {"icon": "play", "label": "Play", "route": "/play"},
+        {"icon": "user", "label": "Profile", "route": "/profile"}
+      ]
+    },
+    "layouts": {
+      "minimal": {
+        "routes": ["/login", "/auth/callback"],
+        "description": "No navigation, centered content"
+      },
+      "game": {
+        "routes": ["/game/:id"],
+        "description": "Full viewport for Phaser, no nav"
+      },
+      "default": {
+        "routes": ["*"],
+        "description": "Sidebar (desktop) / bottom tabs (mobile)"
+      }
+    },
+    "routes": [
+      {"path": "/login", "name": "Login", "auth": "guest", "layout": "minimal", "notes": "OAuth buttons, redirect if logged in"},
+      {"path": "/auth/callback", "name": "AuthCallback", "auth": "none", "layout": "minimal", "notes": "Silent token handling"},
+      {"path": "/starter", "name": "StarterSelection", "auth": "required", "layout": "minimal", "notes": "Redirect here if no starter deck"},
+      {"path": "/", "name": "Dashboard", "auth": "required", "layout": "default", "notes": "Home with widgets (future)"},
+      {"path": "/collection", "name": "Collection", "auth": "required", "layout": "default", "notes": "Card grid with filters"},
+      {"path": "/decks", "name": "DeckList", "auth": "required", "layout": "default", "notes": "List + create button"},
+      {"path": "/decks/new", "name": "NewDeck", "auth": "required", "layout": "default", "notes": "Deck builder (empty)"},
+      {"path": "/decks/:id", "name": "EditDeck", "auth": "required", "layout": "default", "notes": "Deck builder (existing)"},
+      {"path": "/play", "name": "PlayMenu", "auth": "required", "layout": "default", "notes": "Game mode selection"},
+      {"path": "/game/:id", "name": "Game", "auth": "required", "layout": "game", "notes": "Phaser canvas, full viewport"},
+      {"path": "/profile", "name": "Profile", "auth": "required", "layout": "default", "notes": "Display name, avatar, linked accounts, logout"}
+    ],
+    "authFlow": {
+      "loggedOut": "Redirect to /login",
+      "loggedInNoStarter": "Redirect to /starter",
+      "loggedIn": "Allow access to protected routes"
+    },
+    "futureRoutes": [
+      {"path": "/campaign", "backendDep": "Phase 5"},
+      {"path": "/campaign/club/:id", "backendDep": "Phase 5"},
+      {"path": "/matchmaking", "backendDep": "Phase 6"},
+      {"path": "/history", "backendDep": "Phase 6"},
+      {"path": "/packs", "backendDep": "Phase 5"}
+    ],
+    "dashboardWidgets": {
+      "planned": [
+        "Active games (resume)",
+        "Quick play button",
+        "Recent matches",
+        "Collection stats",
+        "Daily rewards (Phase 5+)",
+        "News/announcements"
+      ],
+      "v1": ["Quick play button", "Active games"]
+    },
+    "profilePage": {
+      "v1Features": [
+        "Avatar display",
+        "Display name (editable)",
+        "Linked accounts list",
+        "Logout button"
+      ]
+    }
+  },
+
   "phases": [
     {
       "id": "PHASE_F0",