docs: align evidence and version terminology

[DerMayer1]

What changed

• states that Fencier completed fixture-based policy testing without publishing unsupported benchmark numbers
• explains that numeric results remain withheld until the fixture manifest, policy snapshot, and raw results are checked in
• replaces obsolete phase numbering with version-neutral architecture and product boundaries
• corrects policy fields, Codex skills, prompts, and runbooks that were still described as planned or future work
• documents the implemented --strict exit-code behavior
• distinguishes completed fixture testing from a possible future automated benchmark package

Why

The documentation contained one direct evidence contradiction: the benchmark methodology described testing as future work even though fixture-based testing had been completed. Several other documents also used obsolete phase terminology or described implemented behavior as planned.

This update aligns the repository narrative with current behavior while keeping unsupported numeric claims out of the repository until their source artifacts are available.

Validation

• git diff --check passed
• exactly 8 documentation files changed
• 39 additions and 40 deletions
• no runtime behavior changed
• local fencier verify could not start because the Windows Node host aborts during initialization with Assertion failed: ncrypto::CSPRNG(nullptr, 0)