refactor: finish current workflow architecture cleanup

[tim8es]

Goal

Finish the current-only workflow consolidation without changing supported behavior.

Scope

• rename the sole runtime package from scripts/workflow_v2/ to scripts/workflow/;
• remove remaining legacy schema parsing API;
• fold source/parallel schema validation into the canonical schema module instead of import-time monkey-patching;
• currentize tests/docs/naming;
• preserve current claims, translation acceptance, review, finalize, corpus, EPUB and storage semantics.

TDD state

This PR intentionally starts RED with architecture-contract tests. main remains unchanged until the exact-head Python 3.10/3.12 matrix is fully GREEN.

Historical PR #36 is out of scope and must remain untouched.

[tim8es]

@codex Please implement the exact architecture cleanup defined by the RED tests on this PR. Scope is behavior-preserving only: (1) rename the sole internal runtime package scripts/workflow_v2/ to scripts/workflow/ and update all imports, test filenames/classes, docs/help strings and current references; (2) remove legacy schema API (LEGACY_COMPATIBLE_KINDS, ParsedDocument.legacy, allow_legacy, legacy normalization) and update all callers/tests to the strict current-only API; (3) fold source_schema.py and parallel_schema.py validators directly into canonical schemas.py, remove import-time validator monkey-patching and delete those extension modules; coordination must support only current operations (claim_admission, finalize_admission, proposal_reconcile, translation_acceptance), not workflow upgrade; (4) remove the accidentally committed docs/superpowers/ plan; (5) update naming-only defaults such as workflow-v2 temp lock/commit prefixes to unversioned workflow where safe, without changing durable .workflow/ paths or state semantics; (6) keep all existing behavior and regression coverage, including claims, translation acceptance, review, corpus restore/integrity, GitHub/filesystem storage, finalize, Markdown/EPUB and representative dogfood. Do not touch main or PR #36. Run the full unittest suite and commit the implementation to this PR branch. Do not weaken the new architecture tests.

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[tim8es]

@codex address that feedback

[chatgpt-codex-connector]

To use Codex here, create an environment for this repo.