add MCP support

app/models/mcp_token.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: mcp_tokens
+#
+#  id           :bigint           not null, primary key
+#  archived_at  :datetime
+#  name         :string           not null
+#  sha256       :string           not null
+#  token_prefix :string           not null
+#  created_at   :datetime         not null
+#  updated_at   :datetime         not null
+#  user_id      :bigint           not null
+#
+# Indexes
+#
+#  index_mcp_tokens_on_sha256   (sha256) UNIQUE
+#  index_mcp_tokens_on_user_id  (user_id)
+#
+# Foreign Keys
+#
+#  fk_rails_...  (user_id => users.id)
+#
+class McpToken < ApplicationRecord
+  TOKEN_LENGTH = 43
+
+  belongs_to :user
+
+  before_validation :set_sha256_and_token_prefix, on: :create
+
+  attribute :token, :string, default: -> { SecureRandom.base58(TOKEN_LENGTH) }
+
+  scope :active, -> { where(archived_at: nil) }
+
+  private
+
+  def set_sha256_and_token_prefix
+    self.sha256 = Digest::SHA256.hexdigest(token)
+    self.token_prefix = token[0, 5]
+  end
+end