feat: Add support for minutes in auto resolve feature (#11269)

### Summary

- Converts conversation auto-resolution duration from days to minutes
for more
granular control
- Updates validation to allow values from 10 minutes (minimum) to 999
days (maximum)
- Implements smart messaging to show appropriate time units in activity
messages

###  Changes

- Created migration to convert existing durations from days to minutes
(x1440)
- Updated conversation resolver to use minutes instead of days
- Added dynamic translation key selection based on duration value
- Updated related specs and documentation
- Added support for displaying durations in days, hours, or minutes
based on value

###  Test plan

- Verify account validation accepts new minute-based ranges
- Confirm existing account settings are correctly migrated
- Test auto-resolution works properly with minute values
- Ensure proper time unit display in activity messages

---------

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

app/models/conversation.rb

@@ -76,10 +76,10 @@ class Conversation < ApplicationRecord
   scope :assigned, -> { where.not(assignee_id: nil) }
   scope :assigned_to, ->(agent) { where(assignee_id: agent.id) }
   scope :unattended, -> { where(first_reply_created_at: nil).or(where.not(waiting_since: nil)) }
-  scope :resolvable, lambda { |auto_resolve_duration|
-    return none if auto_resolve_duration.to_i.zero?
+  scope :resolvable, lambda { |auto_resolve_after|
+    return none if auto_resolve_after.to_i.zero?
 
-    open.where('last_activity_at < ? ', Time.now.utc - auto_resolve_duration.days)
+    open.where('last_activity_at < ? AND waiting_since IS NULL', Time.now.utc - auto_resolve_after.minutes)
   }
 
   scope :last_user_message_at, lambda {
@@ -112,7 +112,7 @@ class Conversation < ApplicationRecord
   after_create_commit :notify_conversation_creation
   after_create_commit :load_attributes_created_by_db_triggers
 
-  delegate :auto_resolve_duration, to: :account
+  delegate :auto_resolve_after, to: :account
 
   def can_reply?
     Conversations::MessageWindowService.new(self).can_reply?