v1.9: the per-system method, and the commands that pull the evidence

The per-system method, and the commands that pull the evidence.

• method/collection-rules.md gains eight sections on what each kind of
  system owes and how to reach it. The three-test probe that classifies a
  vendor nobody has met before, on data, commitment and configuration. Why a
  productivity bundle is out of scope while the identity provider and the
  device manager inside it are in. What a system's own drill looks like end to
  end, and the preferred path and the fallback path for the systems most
  companies actually run. What the minimum output for an in-scope system is.
  How the controls that apply to a system are turned into questions a person
  can answer. Why a discovery is recorded the moment it happens rather than
  reconstructed later. And the planning-time reconciliation that stops a
  template, a demo pack or another company's evidence from entering an
  engagement at file one, which is the check that has to run before the first
  file rather than after the eightieth.
• method/commands.md is new: the 72 read-only commands, across 22 systems,
  that pull configuration evidence, each mapped to the Trust Services Criteria
  it helps satisfy. A command_ref in test_attributes.json that names one of
  these systems resolves here. Every command reads configuration and changes
  nothing, and no credential appears in the library as a value.