[backport rh-test] subscription panel (#6140)

## Summary

Backport of #6064 (subscription page) to the `rh-test` branch.

This PR manually cherry-picks commit
7e1e8e3b65 to the rh-test branch and
resolves merge conflicts that prevented automatic backporting.

## Conflicts Resolved

### 1. `src/components/actionbar/ComfyActionbar.vue`
- **Conflict**: HEAD (rh-test) used `<ComfyQueueButton />` while the
subscription PR introduced `<ComfyRunButton />`
- **Resolution**: Updated to use `<ComfyRunButton />` to include the
subscription functionality wrapper while maintaining the existing
rh-test template structure

### 2. `src/composables/auth/useFirebaseAuthActions.ts`
- **Conflict**: Simple ordering difference in the return statement
- **Resolution**: Used the subscription PR's ordering: `deleteAccount,
accessError, reportError`

## Testing

The cherry-pick completed successfully and passed all pre-commit hooks:
- ✅ ESLint
- ✅ Prettier formatting
- ⚠️ Note: 2 unused i18n keys detected (informational only, same as
original PR)

## Related

- Original PR: #6064
- Cherry-picked commit: 7e1e8e3b65

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6140-backport-subscription-page-to-rh-test-2916d73d365081f38f00df422004f61a)
by [Unito](https://www.unito.io)

Co-authored-by: Terry Jia <terryjia88@gmail.com>
Co-authored-by: GitHub Action <action@github.com>

src/locales/en/main.json

@@ -1325,7 +1325,8 @@
     "Notification Preferences": "Notification Preferences",
     "3DViewer": "3DViewer",
     "Vue Nodes": "Vue Nodes",
-    "Canvas Navigation": "Canvas Navigation"
+    "Canvas Navigation": "Canvas Navigation",
+    "PlanCredits": "Plan & Credits"
   },
   "serverConfigItems": {
     "listen": {
@@ -1765,6 +1766,8 @@
     "failedToInitiateCreditPurchase": "Failed to initiate credit purchase: {error}",
     "failedToAccessBillingPortal": "Failed to access billing portal: {error}",
     "failedToPurchaseCredits": "Failed to purchase credits: {error}",
+    "failedToFetchSubscription": "Failed to fetch subscription status: {error}",
+    "failedToInitiateSubscription": "Failed to initiate subscription: {error}",
     "unauthorizedDomain": "Your domain {domain} is not authorized to use this service. Please contact {email} to add your domain to the whitelist.",
     "useApiKeyTip": "Tip: Can't access normal login? Use the Comfy API Key option.",
     "nothingSelected": "Nothing selected",
@@ -1920,6 +1923,35 @@
     "added": "Added",
     "accountInitialized": "Account initialized"
   },
+  "subscription": {
+    "title": "Subscription",
+    "comfyCloud": "Comfy Cloud",
+    "beta": "BETA",
+    "perMonth": "USD / month",
+    "renewsDate": "Renews {date}",
+    "manageSubscription": "Manage subscription",
+    "apiNodesBalance": "\"API Nodes\" Credit Balance",
+    "apiNodesDescription": "For running commercial/proprietary models",
+    "totalCredits": "Total credits",
+    "viewUsageHistory": "View usage history",
+    "addApiCredits": "Add API credits",
+    "yourPlanIncludes": "Your plan includes:",
+    "viewMoreDetails": "View more details",
+    "learnMore": "Learn more",
+    "messageSupport": "Message support",
+    "invoiceHistory": "Invoice history",
+    "benefits": {
+      "benefit1": "$10 in monthly credits for API models — top up when needed",
+      "benefit2": "Up to 30 min runtime per job"
+    },
+    "required": {
+        "title": "Subscribe to",
+      "waitingForSubscription": "Complete your subscription in the new tab. We'll automatically detect when you're done!",
+      "subscribe": "Subscribe"
+    },
+    "subscribeToRun": "Subscribe to Run",
+    "subscribeNow": "Subscribe Now"
+  },
   "userSettings": {
     "title": "User Settings",
     "name": "Name",