feat: migrate AuthUser to main database

This commit completes the migration to consolidate the openneo_id database
into the main openneo_impress database.

Changes:
- AuthUser: Changed from AuthRecord to ApplicationRecord
- AuthUser: Removed explicit table_name (Rails infers 'auth_users')
- AuthUser: Removed all temporary write lock code
- AuthUser: Added TODO comment about future table merge opportunity
- User: Added TODO comment about simplifying remote_id relationship
- AuthRecord: Deleted (no longer needed)
- ApplicationController: Removed temporary rescue_from handler
- database.yml: Removed openneo_id database configuration entirely
- database.yml: Simplified from multi-database (primary:) to single-database structure

The application now runs as a single-database Rails app. The auth_users table
lives in the main openneo_impress database alongside the users table, with
the remote_id relationship preserved.

Next steps for production:
1. Deploy Phase 1 (write lock)
2. Run the CopyAuthUsersTableToMainDatabase migration
3. Deploy this commit (Phase 2)
4. Verify everything works
5. Drop the openneo_id database

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/controllers/application_controller.rb

@@ -27,10 +27,6 @@ class ApplicationController < ActionController::Base
 
   rescue_from ActiveRecord::ConnectionTimeoutError, with: :on_db_timeout
 
-  # TEMPORARY: Rescue handler for database migration write lock
-  # This catches attempts to modify AuthUser records during the migration.
-  rescue_from AuthUser::TemporarilyReadOnly, with: :on_auth_user_read_only
-
   def authenticate_user!
     redirect_to(new_auth_user_session_path) unless user_signed_in?
   end
@@ -77,11 +73,6 @@ class ApplicationController < ActionController::Base
       status: :service_unavailable
   end
 
-  def on_auth_user_read_only
-    flash[:alert] = "Account changes are temporarily unavailable during maintenance. Please try again shortly."
-    redirect_to root_path
-  end
-
   def redirect_back!(default=:back)
     redirect_to(params[:return_to] || default)
   end

app/models/auth_record.rb

@@ -1,5 +0,0 @@
-class AuthRecord < ApplicationRecord
-  self.abstract_class = true
-
-  connects_to database: {reading: :openneo_id, writing: :openneo_id}
-end

app/models/auth_user.rb

@@ -1,39 +1,12 @@
-class AuthUser < AuthRecord
-  self.table_name = 'users'
-
-  # TEMPORARY: Write lock for database migration
-  # During the migration to consolidate databases, we need to prevent writes to
-  # the AuthUser table while keeping reads (like login) working. This will be
-  # removed in the next phase of the migration.
-  class TemporarilyReadOnly < StandardError; end
-
-  # Block all save attempts via before_save callback (more reliable than overriding methods)
-  before_save :prevent_writes_during_migration
-  before_destroy :prevent_writes_during_migration
-
-  def prevent_writes_during_migration
-    raise TemporarilyReadOnly, "Account changes temporarily unavailable during maintenance"
-  end
+class AuthUser < ApplicationRecord
+  # TODO: Consider merging with User model to eliminate the remote_id relationship
+  # and simplify the authentication architecture. This would involve combining the
+  # auth_users and users tables into a single table.
 
   devise :database_authenticatable, :encryptable, :registerable, :validatable,
     :rememberable, :trackable, :recoverable, :omniauthable,
     omniauth_providers: [:neopass]
 
-  # Disable Devise's trackable feature during migration to prevent login tracking updates
-  # This means we'll lose some login tracking data during the migration window, but that's
-  # acceptable compared to breaking logins entirely.
-  def update_tracked_fields!(request)
-    # Normally this would update sign_in_count, current_sign_in_at, etc.
-    # During migration, we just skip it silently.
-  end
-
-  # Disable Devise's rememberable feature during migration to prevent logout from crashing
-  # This means remember_created_at won't be cleared on logout, but that's acceptable.
-  def forget_me!
-    # Normally this would update remember_created_at to nil.
-    # During migration, we just skip it silently.
-  end
-
   validates :name, presence: true, uniqueness: {case_sensitive: false},
     length: {maximum: 30}
 

app/models/user.rb

@@ -3,6 +3,9 @@ class User < ApplicationRecord
 
   PreviewTopContributorsCount = 3
 
+  # TODO: This relationship could be simplified by merging the auth_users and users
+  # tables. Currently User.remote_id points to AuthUser.id, but if the tables were
+  # merged, we could eliminate remote_id and auth_server_id entirely.
   belongs_to :auth_user, foreign_key: :remote_id, inverse_of: :user
   delegate :disconnect_neopass, :uses_neopass?, to: :auth_user
 

config/database.yml

@@ -1,57 +1,28 @@
 development:
-  primary:
-    adapter: mysql2
-    host: <%= ENV.fetch("DB_HOST", "localhost") %>
-    database: openneo_impress
-    username: root
-    pool: 5
-    encoding: utf8mb4
-    collation: utf8mb4_unicode_520_ci
-    variables:
-      sql_mode: TRADITIONAL
-
-  openneo_id:
-    adapter: mysql2
-    host: <%= ENV.fetch("DB_HOST", "localhost") %>
-    database: openneo_id
-    username: root
-    pool: 2
-    variables:
-      sql_mode: TRADITIONAL
-    migrations_paths: db/openneo_id_migrate
+  adapter: mysql2
+  host: <%= ENV.fetch("DB_HOST", "localhost") %>
+  database: openneo_impress
+  username: root
+  pool: 5
+  encoding: utf8mb4
+  collation: utf8mb4_unicode_520_ci
+  variables:
+    sql_mode: TRADITIONAL
 
 test:
-  primary:
-    adapter: mysql2
-    host: <%= ENV.fetch("DB_HOST", "localhost") %>
-    database: openneo_impress_test
-    username: root
-    pool: 5
-    encoding: utf8mb4
-    collation: utf8mb4_unicode_520_ci
-    variables:
-      sql_mode: TRADITIONAL
-
-  openneo_id:
-    adapter: mysql2
-    host: <%= ENV.fetch("DB_HOST", "localhost") %>
-    database: openneo_id_test
-    username: root
-    pool: 2
-    variables:
-      sql_mode: TRADITIONAL
-    migrations_paths: db/openneo_id_migrate
+  adapter: mysql2
+  host: <%= ENV.fetch("DB_HOST", "localhost") %>
+  database: openneo_impress_test
+  username: root
+  pool: 5
+  encoding: utf8mb4
+  collation: utf8mb4_unicode_520_ci
+  variables:
+    sql_mode: TRADITIONAL
 
 production:
-  primary:
-    url: <%= ENV['DATABASE_URL_PRIMARY'] %>
-    encoding: utf8mb4
-    collation: utf8mb4_unicode_520_ci
-    variables:
-      sql_mode: TRADITIONAL
-
-  openneo_id:
-    url: <%= ENV['DATABASE_URL_OPENNEO_ID'] %>
-    variables:
-      sql_mode: TRADITIONAL
-    migrations_paths: db/openneo_id_migrate
+  url: <%= ENV['DATABASE_URL_PRIMARY'] %>
+  encoding: utf8mb4
+  collation: utf8mb4_unicode_520_ci
+  variables:
+    sql_mode: TRADITIONAL