Liquid 5.13.0

Apply the Ruby 4.0 baseline first. For Liquid 5.13.0, the controlled user-template rules below specialize the baseline's trusted-template requirement. They cover the Ruby gem's environments, parsing, rendering, output encoding, drops, extensions, partials, and resource limits.

Template policy and environments

• Accept user-editable Liquid source only within a deliberately restricted capability boundary. Decide which authors, tenants, data, partials, and extensions may share that boundary before accepting templates.
• Build a dedicated Liquid::Environment for each trust profile with Liquid::Environment.build; do not use the process-wide default environment to share mutable tags, filters, loaders, or policy between unrelated applications or tenants.
• Pass the selected environment explicitly as environment: to Liquid::Template.parse. Do not use deprecated Liquid::Template.register_tag, register_filter, or file_system= globals, and never use Liquid::Environment.dangerously_override around concurrent request work.
• Supply a hash mapping approved tag names to classes in Liquid::Environment.build(tags: ...) when authors do not need every standard tag; register extensions inside the build block.
• Review the actual environment.filter_method_names: environments include Liquid::StandardFilters automatically, and registering a module exposes its public instance methods, including inherited ones. Keep helper methods private and verify any required filter restriction explicitly.
• Finalize filter modules, loader configuration, and limit settings before