feat: add contact filter for conversations (#14629)

# Pull Request Template

## Description

Adds a Contact condition to the conversation advanced filter so agents
can search for an existing contact and filter conversations by
`conversations.contact_id`.

Fixes
[CW-7239](https://linear.app/chatwoot/issue/CW-7239/contact-filter-for-conversations)

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality not to work as expected)
- [ ] This change requires a documentation update

## How Has This Been Tested?

- `eval "$(rbenv init -)" && bundle exec rspec
spec/services/conversations/filter_service_spec.rb`
- `pnpm exec vitest --no-watch --no-cache --no-coverage --logHeapUsage
app/javascript/dashboard/components-next/filter/helper/filterHelper.spec.js
app/javascript/dashboard/store/modules/conversations/helpers/specs/filterHelpers.spec.js
app/javascript/dashboard/helper/specs/customViewsHelper.spec.js
app/javascript/dashboard/helper/specs/filterQueryGenerator.spec.js`
- `pnpm eslint`
- `eval "$(rbenv init -)" && bundle exec rubocop
spec/services/conversations/filter_service_spec.rb`

## 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
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>

app/javascript/dashboard/store/modules/conversations/helpers/filterHelpers.js

@@ -73,6 +73,12 @@ const getValueFromConversation = (conversation, attributeKey) => {
       return conversation.display_id || conversation.id;
     case 'assignee_id':
       return conversation.meta?.assignee?.id;
+    case 'contact_id':
+      return (
+        conversation.meta?.sender?.id ||
+        conversation.contact?.id ||
+        conversation.contact_id
+      );
     case 'inbox_id':
       return conversation.inbox_id;
     case 'team_id':

app/javascript/dashboard/store/modules/conversations/helpers/specs/filterHelpers.spec.js

@@ -244,6 +244,32 @@ describe('filterHelpers', () => {
       expect(matchesFilters(conversation, filters)).toBe(false);
     });
 
+    it('should match conversation with equal_to operator for contact_id', () => {
+      const conversation = { meta: { sender: { id: 42 } } };
+      const filters = [
+        {
+          attribute_key: 'contact_id',
+          filter_operator: 'equal_to',
+          values: { id: 42, name: 'Jane Doe' },
+          query_operator: 'and',
+        },
+      ];
+      expect(matchesFilters(conversation, filters)).toBe(true);
+    });
+
+    it('should match conversation with saved contact_id filter values', () => {
+      const conversation = { meta: { sender: { id: 42 } } };
+      const filters = [
+        {
+          attribute_key: 'contact_id',
+          filter_operator: 'equal_to',
+          values: [42],
+          query_operator: 'and',
+        },
+      ];
+      expect(matchesFilters(conversation, filters)).toBe(true);
+    });
+
     // Standard attribute tests - priority
     it('should match conversation with equal_to operator for priority', () => {
       const conversation = { priority: 'urgent' };