Add per-account storage exceptions for SaaS (#2733)

Allow granting specific accounts more storage via an
account_storage_exceptions table in the saas DB, without
relying on the blanket staff bypass.

saas/db/migrate/20260319142914_create_account_storage_exceptions.rb

@@ -0,0 +1,10 @@
+class CreateAccountStorageExceptions < ActiveRecord::Migration[8.2]
+  def change
+    create_table :account_storage_exceptions, id: :uuid do |t|
+      t.references :account, null: false, type: :uuid, index: { unique: true }
+      t.bigint :bytes_allowed, null: false
+
+      t.timestamps
+    end
+  end
+end

saas/db/saas_schema.rb

@@ -10,7 +10,15 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.2].define(version: 2026_03_17_000000) do
+ActiveRecord::Schema[8.2].define(version: 2026_03_19_142914) do
+  create_table "account_storage_exceptions", id: :uuid, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.uuid "account_id", null: false
+    t.bigint "bytes_allowed", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["account_id"], name: "index_account_storage_exceptions_on_account_id", unique: true
+  end
+
   create_table "action_push_native_devices", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.datetime "created_at", null: false
     t.string "name"