feat: Add sidebar unread counts for filters (CW-7262) (#14726)

## Description

Extends the conversation unread-count system so the left sidebar can
show unread badges for Mentions, Participating, Unattended, and saved
conversation folders. Folder badges reuse the existing `custom_filters`
conversation filter semantics, store user-scoped Redis sets lazily, and
skip unsupported folder filters so invalid saved folders continue to
render without a badge. The Unattended badge counts all visible unread
open conversations that match the existing unattended conversation
scope.

Closes
-
[CW-7262](https://linear.app/chatwoot/issue/CW-7262/unread-counts-for-filters-folders)

## What changed

- Added user-scoped unread-count Redis keys and cache builders for
mentions, participating conversations, unattended conversations, and
saved folder filters.
- Reused `Conversations::FilterService` through a relation-returning
path so folder counts match the folder conversation list behavior.
- Invalidated user filter caches from mention, participant,
custom-filter, and relevant conversation update events.
- Extended the unread-count endpoint payload and sidebar Vuex/sidebar
rendering for the new badge counts, including the Unattended sidebar
item.
- Added Ruby, Enterprise, request, listener, and frontend store coverage
for the new unread-count dimensions.

## Type of change

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

## How Has This Been Tested?

- Created local validation folders for `john@acme.inc` and confirmed the
unread-count payload includes open, resolved, and high-priority folder
badges while excluding the invalid unsupported folder.
- Added coverage for the Unattended badge rule: all visible unread open
conversations matching `Conversation.unattended`.
- Ran focused unread-count Ruby specs, including service, listener,
request, and Enterprise counter coverage.
- Ran frontend unread-count store specs.
- Ran RuboCop on the touched Ruby files.
- Ran ESLint through the project script; it completed with warnings in
existing unrelated files and no errors.

<img width="369" height="525" alt="Screenshot 2026-06-13 at 10 51 39 PM"
src="https://github.com/user-attachments/assets/36b1d2c4-dac1-4f6f-9c0e-7ef5a6cc2975"
/>

## 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
- [x] Documentation changes are not required for this internal
unread-count behavior
- [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] No dependent downstream changes are required

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

spec/controllers/api/v1/accounts/conversations_controller_spec.rb

@@ -123,7 +123,7 @@ RSpec.describe 'Conversations API', type: :request do
       end
 
       after do
-        Conversations::UnreadCounts::Store.clear_account!(account.id)
+        Conversations::UnreadCounts::Store.clear_all_account!(account.id)
       end
 
       context 'when conversation unread counts feature is enabled' do
@@ -144,7 +144,42 @@ RSpec.describe 'Conversations API', type: :request do
             'all_count' => 1,
             'inboxes' => { visible_inbox.id.to_s => 1 },
             'labels' => { label.id.to_s => 1 },
-            'teams' => {}
+            'teams' => {},
+            'mentions_count' => 0,
+            'participating_count' => 0,
+            'unattended_count' => 1,
+            'folders' => {}
+          )
+        end
+
+        it 'returns unread counts for mentions, participating conversations, unattended conversations, and folders' do
+          mentioned_conversation = create_unread_conversation(account: account, inbox: visible_inbox)
+          participating_conversation = create_unread_conversation(account: account, inbox: visible_inbox)
+          resolved_conversation = create_unread_conversation(account: account, inbox: visible_inbox)
+          resolved_conversation.update!(status: :resolved)
+          custom_filter = create(:custom_filter, account: account, user: agent, filter_type: :conversation, query: {
+                                   payload: [{
+                                     attribute_key: 'status',
+                                     filter_operator: 'equal_to',
+                                     values: ['resolved'],
+                                     query_operator: nil,
+                                     custom_attribute_type: ''
+                                   }]
+                                 })
+
+          create(:mention, account: account, conversation: mentioned_conversation, user: agent)
+          create(:conversation_participant, account: account, conversation: participating_conversation, user: agent)
+
+          get "/api/v1/accounts/#{account.id}/conversations/unread_counts",
+              headers: agent.create_new_auth_token,
+              as: :json
+
+          expect(response).to have_http_status(:success)
+          expect(response.parsed_body['payload']).to include(
+            'mentions_count' => 1,
+            'participating_count' => 1,
+            'unattended_count' => 2,
+            'folders' => { custom_filter.id.to_s => 1 }
           )
         end
 
@@ -862,7 +897,7 @@ RSpec.describe 'Conversations API', type: :request do
         expect(response).to have_http_status(:success)
         expect(Conversations::UnreadCounts::Store.counts_for_keys([inbox_key])).to eq(inbox_key => 0)
       ensure
-        Conversations::UnreadCounts::Store.clear_account!(account.id)
+        Conversations::UnreadCounts::Store.clear_all_account!(account.id)
       end
 
       it 'updates both if one timestamp is old even when the other is recent' do
@@ -949,7 +984,7 @@ RSpec.describe 'Conversations API', type: :request do
         expect(response).to have_http_status(:success)
         expect(Conversations::UnreadCounts::Store.counts_for_keys([inbox_key])).to eq(inbox_key => 1)
       ensure
-        Conversations::UnreadCounts::Store.clear_account!(account.id)
+        Conversations::UnreadCounts::Store.clear_all_account!(account.id)
       end
     end
   end