feat: Add frontend changes for Captain limits (#10749)

This PR introduces several improvements to the Captain AI dashboard
section:

- New billing page, with new colors, layout and meters for Captain usage
- Updated the base paywall component to use new colors
- Updated PageLayout.vue, it's more generic and can be used for other
pages as well
   - Use flags to toggle empty state and loading state
- Add prop for `featureFlag` to show the paywall slot based on feature
enabled on account
- Update `useAccount` to add a `isCloudFeatureEnabled`
- **Removed feature flag checks from captain route definitions**, so the
captain entry will always be visible on the sidebar
- Add banner to Captain pages for the following cases
   - Responses usage is over 80%
   - Documents limit is fully exhausted


### Screenshots

<details><summary>Free plan</summary>
<p>

![CleanShot 2025-01-22 at 18 37
11@2x](https://github.com/user-attachments/assets/17d3ddba-9095-4e81-9b6f-45b5f69e6a3f)
![CleanShot 2025-01-22 at 18 37
04@2x](https://github.com/user-attachments/assets/df9bb0a6-085f-45da-97d4-74cbcc33fc7e)


</p>
</details> 

<details><summary>Paid plan</summary>
<p>

![CleanShot 2025-01-22 at 18 36
45@2x](https://github.com/user-attachments/assets/a7ccf9d4-143b-49e4-8149-83c7a7985023)

![CleanShot 2025-01-22 at 20 23
57@2x](https://github.com/user-attachments/assets/c6ce35ba-e537-486d-85c8-4cc2d4e76438)


</p>
</details>

---------

Co-authored-by: Sojan Jose <sojan@pepalo.com>
Co-authored-by: Pranav <pranav@chatwoot.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/javascript/dashboard/i18n/locale/en/integrations.json

@@ -309,6 +309,22 @@
       "USE": "Use this",
       "RESET": "Reset"
     },
+    "PAYWALL": {
+      "TITLE": "Upgrade to use Captain AI",
+      "AVAILABLE_ON": "Captain is not available on the free plan.",
+      "UPGRADE_PROMPT": "Upgrade your plan to get access to our assistants, copilot and more.",
+      "UPGRADE_NOW": "Upgrade now",
+      "CANCEL_ANYTIME": "You can change or cancel your plan anytime"
+    },
+    "ENTERPRISE_PAYWALL": {
+      "AVAILABLE_ON": "Captain AI feature is only available in a paid plan.",
+      "UPGRADE_PROMPT": "Upgrade your plan to get access to our assistants, copilot and more.",
+      "ASK_ADMIN": "Please reach out to your administrator for the upgrade."
+    },
+    "BANNER": {
+      "RESPONSES": "You've used over 80% of your response limit. To continue using Captain AI, please upgrade.",
+      "DOCUMENTS": "Document limit reached. Upgrade to continue using Captain AI."
+    },
     "FORM": {
       "CANCEL": "Cancel",
       "CREATE": "Create",
@@ -364,7 +380,7 @@
       },
       "EMPTY_STATE": {
         "TITLE": "No assistants available",
-        "SUBTITLE": "Create an assistant to provide quick and accurate responses to your users. It can learn from your help articles and past conversations. Click the button below to get started."
+        "SUBTITLE": "Create an assistant to provide quick and accurate responses to your users. It can learn from your help articles and past conversations."
       }
     },
     "DOCUMENTS": {
@@ -406,13 +422,13 @@
       },
       "EMPTY_STATE": {
         "TITLE": "No documents available",
-        "SUBTITLE": "Documents are used by your assistant to generate FAQs. You can import documents to provide context for your assistant. Click the button below to get started."
+        "SUBTITLE": "Documents are used by your assistant to generate FAQs. You can import documents to provide context for your assistant."
       }
     },
     "RESPONSES": {
       "HEADER": "FAQs",
       "ADD_NEW": "Create new FAQ",
-      "DOCUMENTABLE" : {
+      "DOCUMENTABLE": {
         "CONVERSATION": "Conversation #{id}"
       },
       "DELETE": {
@@ -422,7 +438,7 @@
         "SUCCESS_MESSAGE": "FAQ deleted successfully",
         "ERROR_MESSAGE": "There was an error deleting the FAQ, please try again."
       },
-      "FILTER" :{
+      "FILTER": {
         "ASSISTANT": "Assistant: {selected}",
         "STATUS": "Status: {selected}",
         "ALL_ASSISTANTS": "All"
@@ -470,7 +486,7 @@
       },
       "EMPTY_STATE": {
         "TITLE": "No FAQs Found",
-        "SUBTITLE": "FAQs help your assistant provide quick and accurate answers to questions from your customers. They can be generated automatically from your content or can be added manually. Click the button below to create your first FAQ."
+        "SUBTITLE": "FAQs help your assistant provide quick and accurate answers to questions from your customers. They can be generated automatically from your content or can be added manually."
       }
     },
     "INBOXES": {
@@ -501,7 +517,7 @@
       },
       "EMPTY_STATE": {
         "TITLE": "No Connected Inboxes",
-        "SUBTITLE": "Connecting an inbox allows the assistant to handle initial questions from your customers before transferring them to you. Click the button below to set it up now."
+        "SUBTITLE": "Connecting an inbox allows the assistant to handle initial questions from your customers before transferring them to you."
       }
     }
   }