Update StateQuerying#effective_state to read column directly

What does this MR do and why?

Reads Namespace#effective_state from the state column instead of ancestor traversal, behind the namespace_state_propagation feature flag.

• Flag ON → direct column/attribute read (state_name)
• Flag OFF → search for inherited state from the closest ancestor.

This is the first step toward eliminating recursive state resolution. Future work will route archived? and deletion_scheduled? through effective_state.

References

• Closes #599306 (closed)
• Parent epic: &21923

How to set up and validate locally

1. Run the following demo script in the rails console

flag = :namespace_state_propagation

original_flag_state = Feature.enabled?(flag)
original_log_level  = Rails.logger.level
Rails.logger.level  = Logger::ERROR # silence SQL and feature-flag warnings

begin
  ActiveRecord::Base.transaction do
    org    = Organizations::Organization.first
    suffix = SecureRandom.hex(4)

    root  = Group.create!(name: "sp-root-#{suffix}",  path: "sp-root-#{suffix}",  organization: org)
    child = Group.create!(name: "sp-child-#{suffix}", path: "sp-child-#{suffix}", organization: org, parent: root)

    root.update!(state: :archived)
    child.update!(state: :ancestor_inherited)
    child.reload

    puts "root state=#{root.state}  child state=#{child.state}  child traversal_ids=#{child.traversal_ids.inspect}"
    puts "-" * 70

    Feature.enable(flag)
    on = child.reload.effective_state
    puts "flag ON  -> child.effective_state = #{on.inspect}  (expected :ancestor_inherited — direct column read)"

    Feature.disable(flag)
    off = child.reload.effective_state
    puts "flag OFF -> child.effective_state = #{off.inspect}  (expected :archived — resolved from ancestor)"

    puts "-" * 70
    if on == :ancestor_inherited && off == :archived
      puts "RESULT: PASS — flag ON returns the direct state; flag OFF resolves the ancestor state."
    else
      puts "RESULT: FAIL — unexpected values (ON=#{on.inspect}, OFF=#{off.inspect})."
    end

    raise ActiveRecord::Rollback
  end
ensure
  original_flag_state ? Feature.enable(flag) : Feature.disable(flag)
  Rails.logger.level = original_log_level
end

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