feat: Add support for search_conversations in copilot (#11520)

Earlier, we were manually checking if a user was an agent and filtering
their conversations based on inboxes. This logic should have been part
of the conversation permissions service.

This PR moves the check to the right place and updates the logic
accordingly.

Other updates:
- Add support for search_conversations service for copilot.
- Use PermissionFilterService in contacts/conversations, conversations,
copilot search_conversations.

---------

Co-authored-by: Sojan <sojan@pepalo.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

enterprise/app/services/captain/tools/copilot/search_conversations_service.rb

@@ -0,0 +1,72 @@
+class Captain::Tools::Copilot::SearchConversationsService < Captain::Tools::BaseService
+  def name
+    'search_conversations'
+  end
+
+  def description
+    'Search conversations based on parameters'
+  end
+
+  def parameters
+    {
+      type: 'object',
+      properties: properties,
+      required: []
+    }
+  end
+
+  def execute(arguments)
+    status = arguments['status']
+    contact_id = arguments['contact_id']
+    priority = arguments['priority']
+
+    conversations = get_conversations(status, contact_id, priority)
+
+    return 'No conversations found' unless conversations.exists?
+
+    total_count = conversations.count
+    conversations = conversations.limit(100)
+
+    <<~RESPONSE
+      #{total_count > 100 ? "Found #{total_count} conversations (showing first 100)" : "Total number of conversations: #{total_count}"}
+      #{conversations.map { |conversation| conversation.to_llm_text(include_contact_details: true) }.join("\n---\n")}
+    RESPONSE
+  end
+
+  private
+
+  def get_conversations(status, contact_id, priority)
+    conversations = permissible_conversations
+    conversations = conversations.where(contact_id: contact_id) if contact_id.present?
+    conversations = conversations.where(status: status) if status.present?
+    conversations = conversations.where(priority: priority) if priority.present?
+    conversations
+  end
+
+  def permissible_conversations
+    Conversations::PermissionFilterService.new(
+      @assistant.account.conversations,
+      @user,
+      @assistant.account
+    ).perform
+  end
+
+  def properties
+    {
+      contact_id: {
+        type: 'number',
+        description: 'Filter conversations by contact ID'
+      },
+      status: {
+        type: 'string',
+        enum: %w[open resolved pending snoozed],
+        description: 'Filter conversations by status'
+      },
+      priority: {
+        type: 'string',
+        enum: %w[low medium high urgent],
+        description: 'Filter conversations by priority'
+      }
+    }
+  end
+end