Release: publish and qualify Board clarity v1.4.2

[jeffhuber]

Part of #945 and roadmap #900.

Problem

Board clarity is not complete until the integrated local behavior ships as a reproducible v1.4.2 package, survives upgrade/restart, and records sanitized release evidence without widening cloud contracts.

Scope

Prepare v1.4.2 version/changelog/release notes/current docs, package artifacts, fresh install and upgrade rehearsal, release-readiness evidence, exact-head review, GitHub release, TestPyPI/PyPI publication, published-package campaign, local installation, three-Board restart/verification, and existing allowlisted CodeMower.com metadata upload. Record design limitations and the handoff to #921/#923.

Do not add or alter cloud event fields. Slack-specific and paired hosted mappings remain #921. This is a serial release child, not an umbrella implementation PR.

Dependencies

• Board: integrate head-bound evidence and qualify local and hosted session visibility #951 — integrated evidence and local/hosted qualification.
• Devin v1.4.0 release Release: publish and qualify Code Mower v1.4.0 with Devin peer support #912.
• Graphify v1.4.1 release Release: qualify and publish optional Graphify context in v1.4.1 #915.

Acceptance criteria

• Every required Epic: Board clarity and provider-neutral session visibility for v1.4.2 #945 child is closed with named builder, independent exact-head audit, P0/P1/P2 resolution, CI, gate, privacy, and acceptance evidence.
• Current documentation matches v1.4.2 and distinguishes local Board visibility from future Slack/cloud mapping.
• Clean source, wheel, TestPyPI, production PyPI, cold-install, and 1.4.1-to-1.4.2 upgrade rehearsals pass.
• Git tag, GitHub Release assets, and PyPI wheel/sdist bind the exact release commit/artifacts.
• The installed CLI reports 1.4.2 and all three existing Board processes are safely restarted with preserved repositories/stores and report serving=installed=1.4.2.
• Board doctor and the local/hosted observation canaries pass from the published package.
• Existing campaign/Board upload is previewed before apply and CodeMower.com accepts only already-allowlisted metadata; no new field is required for release.
• Release: qualify and publish Slack session ingress in v1.5.0 #923 lists this accepted release/readiness as its only Board dependency before Slack end-to-end canary and final lifecycle acceptance.

Initial ownership

Serial convergence/release issue. Builder is assigned by the roadmap orchestrator after B5 passes; release mutations remain orchestrator-owned after exact-head approval.

Code Mower delivery

Produce one independently reviewable release PR for this issue. Record the named Code Mower builder, keep one writer on the branch, obtain an independent audit against the exact current head, resolve every P0/P1/P2 finding, and pass focused/full tests, privacy, package/release checks, normal CI, and code-mower/gate. Use dry-run-first metadata-only uploads and no umbrella PR.