Remove the local prohibition on agent-cut non-major releases

[forkwright]

Finding

AGENTS.md locally forbids every agent merge of a release-please PR, even though its header defers universal policy to Kanon and the canonical release authority explicitly assigns green MINOR/PATCH cuts to T0. This duplicated hard-policy statement has drifted in the restrictive direction.

Evidence

• AGENTS.md:37-41 says “Do not merge release-please PRs — operator decides each release cut.”
• Kanon crates/basanos/standards/RELEASES.md:13-38 makes MAJOR operator-only but makes green MINOR/PATCH release-please PRs agent-mergeable through the typed pr_merge policy.
• Draft release PR chore(main): release 0.1.6 #71 is a PATCH cut. It is correctly blocked today by missing checks and Derive public license claims from the PolyForm and documentation artifacts #74, but after those blockers land this local sentence would still contradict the only authoritative merge mechanism.

Why this matters

A repo-local copy of a fleet hard policy creates two authorities. Agents either strand a valid non-major release, solicit unnecessary operator action, or learn to choose whichever prose copy permits the desired outcome. Release authority is an irreversibility-class control and must be single-sourced in the mechanism and its canonical standard.

Desired correction

• Delete the local release-please prohibition from AGENTS.md; do not replace it with another restatement of fleet release policy.
• Keep the existing file-level deferral to Kanon and let pr_merge plus canonical RELEASES.md determine release authority.
• Before chore(main): release 0.1.6 #71 lands, verify its version delta is PATCH, its current-head checks are green, Derive public license claims from the PolyForm and documentation artifacts #74 is resolved, and the normal non-admin pr_merge release path accepts it.

Done when: Dioptron carries no local release-authority fork, and a non-major release is governed only by the canonical typed merge policy while MAJOR remains unreachable to agents.