Remove retired prerelease lifecycle contracts

[rmcdaniel]

Closes #115

What changed

• removes the inactive beta authorization, candidate, continuity, conformance, product-train, release-plan, release-recovery, stable-authorization, Waterline-train, repository-hygiene, and issue-mirror contracts
• removes their dormant scripts, fixtures, tests, and the final release-recovery workflow
• keeps the organization contracts still used by product repositories: GitHub Actions policy, conformance guidance, regression corpus, and bounded visual evidence
• removes retired privileged workflow_run bindings from the action policy and points the control-repository target at its current repository check
• replaces 1,902 lines of beta-oriented qualification tests with focused tests for immutable Action pins, pull-request permissions, cache safety, and the checked-in workflows

This deletes 69,692 lines of launch machinery without replacing it with another lifecycle controller.

Verification

• 66 Python contract tests passed
• 75 browser-boundary tests passed
• Ruff, JSON parsing, Python compilation, and git diff --check passed
• the revised action policy validated the current Workflow, Waterline, AI, Server, CLI, Sample App, PHP SDK, Python SDK, Rust SDK, documentation, and private Cloud workflow inventories