fix: V2 Assignment service enhancements (#13036)

## Linear Ticket:
https://linear.app/chatwoot/issue/CW-6081/review-feedback

## Description

Assignment V2 Service Enhancements

- Enable Assignment V2 on plan upgrade
- Fix UI issue with fair distribution policy display
- Add advanced assignment feature flag and enhance Assignment V2
capabilities

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)

## How Has This Been Tested?

This has been tested using the UI.

## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] 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
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Changes auto-assignment execution paths, rate limiting defaults, and
feature-flag gating (including premium plan behavior), which could
affect which conversations get assigned and when. UI rewires inbox
settings and policy flows, so regressions are possible around
navigation/linking and feature visibility.
> 
> **Overview**
> **Adds a new premium `advanced_assignment` feature flag** and uses it
to gate capacity/balanced assignment features in the UI (sidebar entry,
settings routes, assignment-policy landing cards) and backend
(Enterprise balanced selector + capacity filtering).
`advanced_assignment` is marked premium, included in Business plan
entitlements, and auto-synced in Enterprise accounts when
`assignment_v2` is toggled.
> 
> **Improves Assignment V2 policy UX** by adding an inbox-level
“Conversation Assignment” section (behind `assignment_v2`) that can
link/unlink an assignment policy, navigate to create/edit policy flows
with `inboxId` query context, and show an inbox-link prompt after
creating a policy. The policy form now defaults to enabled, disables the
`balanced` option with a premium badge/message when unavailable, and
inbox lists support click-to-navigate.
> 
> **Tightens/adjusts auto-assignment behavior**: bulk assignment now
requires `inbox.enable_auto_assignment?`, conversation ordering uses the
attached `assignment_policy` priority, and rate limiting uses
`assignment_policy` config with an infinite default limit while still
tracking assignments. Tests and i18n strings are updated accordingly.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
23bc03bf75ee4376071e4d7fc7cd564c601d33d7. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

---------

Co-authored-by: Pranav <pranav@chatwoot.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: Shivam Mishra <scm.mymail@gmail.com>

app/javascript/dashboard/components-next/AssignmentPolicy/components/DataTable.vue

@@ -19,11 +19,15 @@ defineProps({
   },
 });
 
-const emit = defineEmits(['delete']);
+const emit = defineEmits(['delete', 'navigate']);
 
 const handleDelete = itemId => {
   emit('delete', itemId);
 };
+
+const handleNavigate = item => {
+  emit('navigate', item);
+};
 </script>
 
 <template>
@@ -47,7 +51,11 @@ const handleDelete = itemId => {
       :key="item.id"
       class="grid grid-cols-4 items-center gap-3 min-w-0 w-full justify-between h-[3.25rem] ltr:pr-2 rtl:pl-2"
     >
-      <div class="flex items-center gap-2 col-span-2">
+      <button
+        type="button"
+        class="flex items-center gap-2 col-span-2 hover:bg-n-alpha-1 dark:hover:bg-n-alpha-2 rounded-lg py-1 px-1.5 -ml-1.5 transition-colors cursor-pointer group"
+        @click="handleNavigate(item)"
+      >
         <Icon
           v-if="item.icon"
           :icon="item.icon"
@@ -61,10 +69,16 @@ const handleDelete = itemId => {
           :size="20"
           rounded-full
         />
-        <span class="text-sm text-n-slate-12 truncate min-w-0">
+        <span
+          class="text-sm text-n-slate-12 truncate min-w-0 group-hover:text-n-blue-11 dark:group-hover:text-n-blue-10 transition-colors"
+        >
           {{ item.name }}
         </span>
-      </div>
+        <Icon
+          icon="i-lucide-external-link"
+          class="size-3.5 text-n-slate-10 opacity-0 group-hover:opacity-100 transition-opacity flex-shrink-0"
+        />
+      </button>
 
       <div class="flex items-start gap-2 col-span-1">
         <span