feat: scheduler fairness [AI-159] (#14425)

# Pull Request Template

## Description
Better scheduling and queueing mechanics for document auto-sync
- add jitter plan wise for document sync
- move auto-sync documents to purgeable queue

## Type of change

Please delete options that are not relevant.

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

## How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide
instructions so we can reproduce. Please also list any relevant details
for your test configuration.
locally tested and with specs

## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] 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
- [x] 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
- [x] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: Sony Mathew <sony@chatwoot.com>
Co-authored-by: Vishnu Narayanan <iamwishnu@gmail.com>

app/javascript/dashboard/components-next/captain/assistant/DocumentBulkActions.vue

@@ -25,7 +25,7 @@ const store = useStore();
 const bulkDeleteDialog = ref(null);
 
 const isSyncableDocument = doc =>
-  !doc.pdf_document && doc.status === 'available' && !doc.sync_in_progress;
+  !doc.pdf_document && doc.status === 'available';
 
 const syncableSelectedIds = computed(() => {
   if (!props.selectedIds.size) return [];

app/javascript/dashboard/components-next/captain/assistant/DocumentCard.vue

@@ -127,7 +127,6 @@ const menuItems = computed(() => {
       value: 'sync',
       action: 'sync',
       icon: 'i-lucide-refresh-cw',
-      disabled: props.syncInProgress,
     });
   }