Move from sync s3 and azure to only use azure for attachments (#8580)

## Trello card URL
- https://trello.com/c/UtzBnbCV/2097-move-from-aws-s3-to-azure-storage

## Changes in this PR:

- Points the attachments directly to Azure Storage accounts without
going through the Mirror (S3 -> Azure).
- Removes already run rake tasks for the previous setps of the S3 ->
Azure move.
- Backfills the existing attachments to point to the Azure Storage


## Checklists:

### Data & Schema Changes

If this PR modifies data structures or validations, check the following:

- [ ] Adds/removes model validations
- [ ] Adds/removes database fields
- [ ] Modifies Vacancy enumerables (phases, working patterns, job roles,
key stages, etc.)

<details>
<summary>If any of the above options has changed then the author must
check/resolve all of the following...</summary>

### Integration Impact

Does this change affect any of these integrations?
- [ ] DfE Analytics platform
- [ ] Legacy imports mappings
- [ ] DWP Find a Job export mappings
- [ ] Publisher ATS API (may require mapping updates or API versioning)

### User Experience & Data Integrity

Could this change impact:
- [ ] Existing subscription alerts (will legacy subscription search
filters break?)
- [ ] Legacy vacancy copying (will copied vacancies fail new
validations?)
- [ ] In-progress drafts for Vacancies or Job Applications
</details>

Author: scruti

app/models/job_application.rb

@@ -141,7 +141,7 @@ class JobApplication < ApplicationRecord
 
   validates :email_address, email_address: true, if: -> { email_address_changed? } # Allows data created prior to validation to still be valid
 
-  has_one_attached :baptism_certificate, service: :mirror_documents
+  has_one_attached :baptism_certificate, service: :azure_storage_documents
 
   validate :status_transition, if: -> { status_changed? }
 

app/models/organisation.rb

@@ -12,8 +12,8 @@ class Organisation < ApplicationRecord
 
   friendly_id :slug_candidates, use: %i[slugged history]
 
-  has_one_attached :logo, service: :mirror_images_and_logos
-  has_one_attached :photo, service: :mirror_images_and_logos
+  has_one_attached :logo, service: :azure_storage_images_and_logos
+  has_one_attached :photo, service: :azure_storage_images_and_logos
 
   has_many :organisation_vacancies, dependent: :destroy
   has_many :vacancies, through: :organisation_vacancies

app/models/vacancy.rb

@@ -87,12 +87,12 @@ class Vacancy < ApplicationRecord
     valid_file_types: %i[PDF DOC DOCX],
   }.freeze
 
-  has_many_attached :supporting_documents, service: :mirror_documents
+  has_many_attached :supporting_documents, service: :azure_storage_documents
 
   validates :supporting_documents, content_type: DOCUMENT_CONTENT_TYPES,
                                    size: { less_than: DOCUMENT_FILE_SIZE_LIMIT }, virus_free: true, if: -> { include_additional_documents }
 
-  has_one_attached :application_form, service: :mirror_documents
+  has_one_attached :application_form, service: :azure_storage_documents
 
   has_many :saved_jobs, dependent: :destroy
   has_many :saved_by, through: :saved_jobs, source: :jobseeker

config/environments/production.rb

@@ -5,7 +5,7 @@
 
   # The application uses multiple services for storing files. This sets up a default value which gets overridden
   # in every specific use case.
-  config.active_storage.service = :mirror_documents
+  config.active_storage.service = :azure_storage_documents
 
   # Configure the domains permitted to access coordinates API
   config.allowed_cors_origin = proc { "https://#{DOMAIN}" }

lib/tasks/backfill_azure_storage.rake

@@ -0,0 +1,37 @@
+desc "Point existing attachments from mirror services to Azure storage directly"
+
+task point_existing_attachments_to_azure_storage: :environment do
+  puts "Starting migration of attachments to Azure storage..."
+  puts "=" * 80
+
+  # Migration mapping: from mirror services to direct Azure services
+  # This bypasses the mirror service (which has S3 as primary) and points directly to Azure
+  migrations = {
+    "mirror_documents" => "azure_storage_documents",
+    "mirror_images_and_logos" => "azure_storage_images_and_logos",
+  }
+
+  total_updated = 0
+
+  migrations.each do |old_service, new_service|
+    puts "\nMigrating blobs from '#{old_service}' to '#{new_service}'..."
+
+    blobs = ActiveStorage::Blob.where(service_name: old_service)
+    count = blobs.count
+
+    if count.zero?
+      puts "No blobs found for service '#{old_service}'"
+    else
+      puts "Found #{count} blob(s) to migrate"
+      # Update service names in batches
+      updated_count = blobs.update_all(service_name: new_service)
+      total_updated += updated_count
+      puts "✓ Updated #{updated_count} blob(s) to use '#{new_service}'"
+    end
+  end
+
+  puts "\n#{'=' * 80}"
+  puts "Migration complete!"
+  puts "Total blobs updated: #{total_updated}"
+  puts "=" * 80
+end