[Beta.2 continuous cleanup] Freeze semantic ownership and contribution governance

[SisyphusZheng]

Scheduling amendment: ADR-0152 / #1341. Active lane: Beta.2 continuous cleanup; scope below is retained except superseded train timing. No implementation completion is claimed.

Current scope

Continuous cleanup under #1322 begins during Beta.2.1; no waiting for a former Beta.3 lane. Preserve distinct residual obligations and do not duplicate #1328-#1334/#1156. RC-only qualification remains a later gate.

Part of #1155 and #1192. Target: 1.0.0-alpha.x.

Objective

After architecture stabilizes, reduce current documentation to canonical architecture and active decisions, with GitHub as operational truth.

Scope

• ADR classification and canonical architecture consolidation
• deterministic path/blob migration manifests
• README, CONTRIBUTING, governance, status, roadmap, release-policy, and template cleanup
• removal of per-attempt transcripts, duplicated logs, release journals, duplicated version records, and obsolete evidence bundles recoverable from GitHub
• contributor-facing information architecture

Boundary

This issue does not block Alpha implementation. During Alpha, change only the small current contracts and planning authority required by active implementation. Do not perform a repository-wide historical rewrite.

Acceptance

• Current architecture is readable without traversing historical ADR chains.
• Historical bytes remain recoverable through Git history.
• Operational history belongs to Issues, PRs, Actions, Checks, Rulesets, Releases, and provenance systems.
• Durable repository evidence is compact.