ci(mobile): add EAS-based release workflow for the mobile app

- .github/workflows/mobile-release.yml: validate (npm ci + tsc) on every
  run with no secrets, plus an EAS Build job gated on workflow_dispatch or
  a `mobile-v*` tag. Requires only the EXPO_TOKEN secret.
- app/eas.json: development / preview (iOS simulator, no Apple account) /
  production (signed, EAS-managed Apple credentials) build profiles.

app/eas.json

@@ -0,0 +1,24 @@
+{
+  "cli": {
+    "version": ">= 12.0.0",
+    "appVersionSource": "local"
+  },
+  "build": {
+    "development": {
+      "developmentClient": true,
+      "distribution": "internal"
+    },
+    "preview": {
+      "distribution": "internal",
+      "ios": {
+        "simulator": true
+      }
+    },
+    "production": {
+      "autoIncrement": true
+    }
+  },
+  "submit": {
+    "production": {}
+  }
+}