Fix account destroy cascade gaps

Account incineration could leave orphaned records due to missing cascade
declarations and async jobs failing when the account was already gone.

Cascade fixes:
- Add Account::Searchable concern to clean up Search::Query (delete_all)
  and Search::Record (destroy_all, respects SQLite FTS dependent: :destroy)
- Add before_destroy in Account::Storage to delete storage entries
- Suppress storage entry recording during incineration so attachment
  purge callbacks don't create entries or enqueue materialize jobs
- Guard Access#clean_inaccessible_data_later with unless user.destroyed?
  to avoid enqueuing pointless jobs during user cascade

Job tenancy:
- Extract AccountTenanted concern from the global ActiveJob initializer
  into ApplicationJob (include) with targeted prepends for
  ActionMailer::MailDeliveryJob and Turbo broadcast jobs
- Defer account resolution from deserialize to perform so that missing
  accounts raise DeserializationError inside the execution path where
  discard_on can handle it

Tests:
- Comprehensive incineration test covering 35 model types with
  before/after assertions and full enqueued job processing
- Mailer deliver_later test verifying account context survives job
  serialization for multi-account users
- Turbo broadcast test verifying account-scoped URLs in rendered partials

app/models/access.rb

@@ -19,6 +19,6 @@ class Access < ApplicationRecord
     end
 
     def clean_inaccessible_data_later
-      Board::CleanInaccessibleDataJob.perform_later(user, board)
+      Board::CleanInaccessibleDataJob.perform_later(user, board) unless user.destroyed?
     end
 end

app/models/account.rb

@@ -1,5 +1,5 @@
 class Account < ApplicationRecord
-  include Account::Storage, Cancellable, Entropic, Incineratable, MultiTenantable, Seedeable
+  include Account::Storage, Cancellable, Entropic, Incineratable, MultiTenantable, Searchable, Seedeable
 
   has_one :join_code, dependent: :destroy
   has_many :users, dependent: :destroy

app/models/account/import.rb

@@ -4,7 +4,7 @@ class Account::Import < ApplicationRecord
   belongs_to :account
   belongs_to :identity
 
-  has_one_attached :file
+  has_one_attached :file, dependent: :purge_later
 
   enum :status, %w[ pending processing completed failed ].index_by(&:itself), default: :pending
   enum :failure_reason, %w[ conflict invalid_export ].index_by(&:itself), prefix: :failed_due_to, scopes: false

app/models/account/incineratable.rb

@@ -11,7 +11,7 @@ module Account::Incineratable
 
   def incinerate
     run_callbacks :incinerate do
-      account.destroy
+      Storage::Entry.suppressing_recording { account.destroy }
     end
   end
 end

app/models/account/searchable.rb

@@ -0,0 +1,14 @@
+module Account::Searchable
+  extend ActiveSupport::Concern
+
+  included do
+    has_many :search_queries, class_name: "Search::Query", dependent: :delete_all
+
+    before_destroy :clear_search_records
+  end
+
+  private
+    def clear_search_records
+      Search::Record.for(id).destroy_all
+    end
+end

app/models/account/storage.rb

@@ -2,7 +2,15 @@ module Account::Storage
   extend ActiveSupport::Concern
   include Storage::Totaled
 
+  included do
+    before_destroy :clear_storage_entries
+  end
+
   private
+    def clear_storage_entries
+      Storage::Entry.where(account_id: id).delete_all
+    end
+
     def calculate_real_storage_bytes
       boards.sum { |board| board.send(:calculate_real_storage_bytes) }
     end

app/models/export.rb

@@ -2,7 +2,7 @@ class Export < ApplicationRecord
   belongs_to :account
   belongs_to :user
 
-  has_one_attached :file
+  has_one_attached :file, dependent: :purge_later
 
   enum :status, %w[ pending processing completed failed ].index_by(&:itself), default: :pending
 

app/models/identity.rb

@@ -9,7 +9,7 @@ class Identity < ApplicationRecord
   has_many :users, dependent: :nullify
   has_many :accounts, through: :users
 
-  has_one_attached :avatar
+  has_one_attached :avatar, dependent: :purge_later
 
   before_destroy :deactivate_users, prepend: true
 

app/models/storage/entry.rb

@@ -5,12 +5,22 @@ class Storage::Entry < ApplicationRecord
 
   scope :pending, ->(last_entry_id) { where.not(id: ..last_entry_id) if last_entry_id }
 
+  thread_mattr_accessor :recording, default: true
+
+  def self.suppressing_recording(&block)
+    original, self.recording = self.recording, false
+    yield
+  ensure
+    self.recording = original
+  end
+
   # Records may be destroyed (during cascading deletes) but .id still works.
   # Skip entirely if account is destroyed - no need to track storage for deleted accounts.
   # Skip materialize jobs for destroyed boards since there's nothing to update.
   def self.record(delta:, operation:, account:, board: nil, recordable: nil, blob: nil)
     return if delta.zero?
     return if account.destroyed?
+    return unless recording
 
     entry = create! \
       account_id: account.id,

app/models/user/avatar.rb

@@ -11,7 +11,7 @@ module User::Avatar
   ].freeze
 
   included do
-    has_one_attached :avatar do |attachable|
+    has_one_attached :avatar, dependent: :purge_later do |attachable|
       attachable.variant :thumb, resize_to_fill: [ 256, 256 ], process: :immediately
     end