Much base work started

db/migrate/20251029120500_update_playback_sessions_from_architecture.rb

@@ -0,0 +1,15 @@
+class UpdatePlaybackSessionsFromArchitecture < ActiveRecord::Migration[8.1]
+  def change
+    change_table :playback_sessions do |t|
+      # Add defaults for fields
+      t.change_default :position, 0.0
+      t.change_default :duration_watched, 0.0
+      t.change_default :completed, false
+      t.change_default :play_count, 0
+    end
+
+    # Add indexes as specified in architecture
+    add_index :playback_sessions, [:video_id, :user_id], unique: true
+    add_index :playback_sessions, :last_watched_at
+  end
+end