Add OpenProject Gitea integration plugin

Implements a Gitea integration for OpenProject following the same
patterns as the bundled GitHub and GitLab integrations.

- Webhook endpoint at /webhooks/gitea with HMAC-SHA256 verification
- Handles pull_request and issue_comment events
- Links Gitea PRs to work packages via OP# references or URLs
- Posts journal comments on WPs for PR lifecycle events
- Gitea tab on the work package split view
- V3 API endpoint: GET /api/v3/work_packages/:id/gitea_pull_requests
- Admin settings UI for bot user and webhook secret
- Nightly cron job to clean up unlinked PR records

lib/api/v3/gitea_pull_requests/gitea_pull_request_collection_representer.rb

@@ -0,0 +1,37 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See COPYRIGHT and LICENSE files for more details.
+#++
+
+module API
+  module V3
+    module GiteaPullRequests
+      class GiteaPullRequestCollectionRepresenter < ::API::Decorators::UnpaginatedCollection
+        element_representer ::API::V3::GiteaPullRequests::GiteaPullRequestRepresenter
+      end
+    end
+  end
+end

lib/api/v3/gitea_pull_requests/gitea_pull_request_representer.rb

@@ -0,0 +1,98 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See COPYRIGHT and LICENSE files for more details.
+#++
+
+require "roar/decorator"
+require "roar/json/hal"
+
+module API
+  module V3
+    module GiteaPullRequests
+      class GiteaPullRequestRepresenter < ::API::Decorators::Single
+        include API::Caching::CachedRepresenter
+        include API::Decorators::DateProperty
+        include API::Decorators::FormattableProperty
+        include API::Decorators::LinkedResource
+
+        def initialize(model, current_user:, **_opts)
+          super(model, current_user:, embed_links: true)
+        end
+
+        cached_representer key_parts: %i[gitea_user merged_by]
+
+        property :id
+
+        property :number
+
+        property :gitea_html_url, as: :htmlUrl
+
+        property :state,
+                 render_nil: true
+
+        property :repository,
+                 render_nil: true
+
+        date_time_property :gitea_updated_at,
+                           render_nil: true,
+                           setter: ->(*) {}
+
+        property :title,
+                 render_nil: true
+
+        formattable_property :body,
+                             render_nil: true
+
+        property :draft,
+                 render_nil: true
+
+        property :merged,
+                 render_nil: true
+
+        property :labels
+
+        associated_resource :gitea_user,
+                            representer: ::API::V3::GiteaPullRequests::GiteaUserRepresenter,
+                            link_title_attribute: :gitea_login
+
+        associated_resource :merged_by,
+                            representer: ::API::V3::GiteaPullRequests::GiteaUserRepresenter,
+                            v3_path: :gitea_user,
+                            link_title_attribute: :gitea_login
+
+        date_time_property :created_at
+
+        date_time_property :updated_at
+
+        def _type
+          "GiteaPullRequest"
+        end
+
+        self.to_eager_load = %i[gitea_user merged_by]
+      end
+    end
+  end
+end

lib/api/v3/gitea_pull_requests/gitea_pull_requests_by_work_package_api.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See COPYRIGHT and LICENSE files for more details.
+#++
+
+module API
+  module V3
+    module GiteaPullRequests
+      class GiteaPullRequestsByWorkPackageAPI < ::API::OpenProjectAPI
+        after_validation do
+          authorize_in_work_package(:show_gitea_content, work_package: @work_package)
+          @gitea_pull_requests = @work_package.gitea_pull_requests
+        end
+
+        resources :gitea_pull_requests do
+          get do
+            path = api_v3_paths.gitea_pull_requests_by_work_package(@work_package.id)
+            GiteaPullRequestCollectionRepresenter.new(@gitea_pull_requests,
+                                                      @gitea_pull_requests.count,
+                                                      self_link: path,
+                                                      current_user:)
+          end
+        end
+      end
+    end
+  end
+end

lib/api/v3/gitea_pull_requests/gitea_user_representer.rb

@@ -0,0 +1,52 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See COPYRIGHT and LICENSE files for more details.
+#++
+
+require "roar/decorator"
+require "roar/json/hal"
+
+module API
+  module V3
+    module GiteaPullRequests
+      class GiteaUserRepresenter < ::API::Decorators::Single
+        property :id
+
+        property :gitea_id, as: :giteaId
+
+        property :gitea_name, as: :name
+
+        property :gitea_login, as: :login
+
+        property :gitea_avatar_url, as: :avatarUrl
+
+        def _type
+          "GiteaUser"
+        end
+      end
+    end
+  end
+end