docs: plan version 1.0 release readiness and acceptance

[rogerdigital]

Prepare the existing five export formats for 1.0.0 with an implementation plan covering output collision protection, explicit partial and cancelled results, documentation, version checks, and release gates.

The companion acceptance protocol defines reproducible synthetic fixtures, native artifact and platform checks, upgrade validation, and verification of published assets. Required checks distinguish unavailable environments from passing results. This PR changes documentation only; it does not implement fixes or publish a release.

Validation:

• Document links, code fences, whitespace, and staged diff checks passed.
• The embedded fixture generator produced 520 synthetic files and correctly refused a second run into the non-empty destination.
• Product tests and native acceptance were not rerun for this documentation-only change.