Canonical NEXT in bounded v1

Use cli/ok -C ROOT next (or the root's .overseer/bin/ok). It reads only docs/NEXT.md for the current action. ROADMAP and HANDOVER summarize the state; neither is a fallback prompt source. Unknown, stale, foreign, or malformed NEXT produces a nonzero refusal and no prompt.

NEXT has strict YAML frontmatter for schema, repository UUID/root, branch, base HEAD, lane, model, action ID, action kind, and prompt SHA-256, followed by the exact UTF-8 prompt. next-write is its single supported publisher. See the repository README for required expected-context arguments and compare-before-write behavior.

Schema 2 adds vcs (git or muse) and source_id (the Muse repository ID, or null for Git). Existing schema-1 NEXT is accepted only with Git authority. The base revision belongs to the selected backend; a Git mirror revision never substitutes for a Muse revision. Muse writers require explicit --vcs muse and --base-head REVISION as well as the existing context and prior NEXT digest.

Commit application work before publishing ignored NEXT. A later Muse commit always makes NEXT stale. The legacy Git exception for one closing commit that contains the exact tracked NEXT bytes remains supported; newly ignored NEXT does not use it. Adopting a different backend preserves NEXT bytes but refuses them until explicitly republished for the new authority. No task is inferred.

The former synchronization alias and legacy prompt extraction are historical and not supported by the v1 launcher. On closeout print CURRENT NEXT from disk.