Phase 1: warp_engine gem skeleton (path gem, mounted engine)

- libs/ruby/warp_engine: gemspec, WarpEngine::Engine (isolate_namespace with
  empty table_name_prefix), WarpEngine.configure surface (container paths,
  update_secret, image_owners), empty engine routes
- host Gemfile: path gem; host routes: mount WarpEngine::Engine => "/" as
  the last entry so host routes always win
- docker: api build context moved to repo root so libs/ is visible at
  bundle-install time; ./libs:/libs runtime mount; root .dockerignore to keep
  data/ and node_modules out of the build context

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

lib/warp_engine.rb

@@ -0,0 +1,21 @@
+require "warp_engine/version"
+require "warp_engine/configuration"
+
+module WarpEngine
+  # A tábláink prefix nélküliek (softwares, releases, ...) — az isolate_namespace
+  # által generált "warp_engine_" prefixet üresre cseréljük. Az engine.rb require-je
+  # előtt kell definiálva lennie.
+  def self.table_name_prefix
+    ""
+  end
+
+  def self.config
+    @config ||= Configuration.new
+  end
+
+  def self.configure
+    yield(config)
+  end
+end
+
+require "warp_engine/engine"