feat: Update Captain navigation structure (#12761)

# Pull Request Template

## Description

This PR includes an update to the Captain navigation structure.

## Route Structure

```javascript
1. captain_assistants_responses_index    → /captain/:assistantId/faqs
2. captain_assistants_documents_index    → /captain/:assistantId/documents
3. captain_assistants_scenarios_index    → /captain/:assistantId/scenarios
4. captain_assistants_playground_index   → /captain/:assistantId/playground
5. captain_assistants_inboxes_index      → /captain/:assistantId/inboxes
6. captain_tools_index                   → /captain/tools
7. captain_assistants_settings_index     → /captain/:assistantId/settings
8. captain_assistants_guardrails_index   → /captain/:assistantId/settings/guardrails
9. captain_assistants_guidelines_index   → /captain/:assistantId/settings/guidelines
10. captain_assistants_index             → /captain/:navigationPath
```

**How it works:**

1. User clicks sidebar item → Routes to `captain_assistants_index` with
`navigationPath`
2. `AssistantsIndexPage` validates route and gets last active assistant,
if not redirects to assistant create page.
3. Routes to actual page: `/captain/:assistantId/:page`
4. Page loads with correct assistant context

Fixes
https://linear.app/chatwoot/issue/CW-5832/updating-captain-navigation

## Type of change

- [x] New feature (non-breaking change which adds functionality)

## How Has This Been Tested?




## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

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

app/javascript/dashboard/components-next/copilot/CopilotEmptyState.vue

@@ -78,8 +78,10 @@ const handleSuggestion = opt => {
       </p>
       <router-link
         :to="{
-          name: 'captain_assistants_index',
-          params: { accountId: route.params.accountId },
+          name: 'captain_assistants_create_index',
+          params: {
+            accountId: route.params.accountId,
+          },
         }"
         class="text-n-slate-11 underline hover:text-n-slate-12"
       >