Add menu-order accessors #4

Status: completed

Epic: E3 — Minimal 1.0 public API

Goal: Provide symmetric public accessors for the WordPress menu_order field.

Scope:

• Add getMenuOrder(): int and chainable setMenuOrder(int $menuOrder): self behavior.
• Add the methods to the stable interface contract.
• Persist the value through the existing savePost() lifecycle.
• Cover zero, positive, negative, successful persistence, reload, and save-failure state.
• Update API, migration, and changelog documentation.

Out of Scope:

• Reordering adjacent posts.
• Enforcing application-specific menu-order ranges.
• Automatic saving from the setter.

DoR:

• 0.7.0 is published and verified.
• Naming and chainability are approved by the 1.0 API gate.

DoD:

• Interface, trait, tests, and docs expose the same contract.
• Real WordPress persists and reloads integer menu order correctly.
• Existing post fields are unaffected.

AC:

• Given a loaded post, getMenuOrder() returns its integer menu_order value.
• Given setMenuOrder(), the in-memory value changes and the same instance is returned.
• Given savePost() and reload, the new value is returned.

Dependencies:

• T8 — Publish 0.7.0.

Artifacts:

• Interface and trait changes
• Unit and integration tests
• API/changelog documentation

Verification:

• Unit suite on PHP 7.4 and 8.4.
• WordPress 6.0 and latest integration profiles.

Notes/Risks:

• Negative values are valid integers at the library layer and persisted by both supported WordPress integration edges.
• The library intentionally makes no range, reordering, or query-semantics promise.

Readiness evidence:

• T8/0.7.0 is published, independently verified, and completed.
• Accepted ADR 0001 explicitly includes symmetric menu-order accessors; the approved task contract fixes get/set naming and setter chainability.

Execution evidence:

• Batch 4 runs on branch codex/1.0-api-batch-4 after T8/E2 closure.
• Implementation, dedicated tests, migration notes, and user/testing documentation are committed as dde6dc6.
• make check and the direct PHP 7.4 unit suite: 59 tests, 354 assertions on PHP 8.4 and 7.4.
• make coverage: 180/180 source lines and 43/43 methods (100%).
• make test.package-install and make smoke: pass.
• Minimum artifact minimum-20260910T232558Z-42780-14671: WordPress 6.0 / PHP 7.4.33, pass, zero remaining fixtures.
• Latest artifact latest-20260910T232631Z-44008-10331: WordPress 7.1 / PHP 8.4.25, pass, zero remaining fixtures.
• Both real profiles proved positive, zero, and negative persistence. A forced Core WP_Error retained -7 in memory, left the database at 0, and a retry persisted -7 without altering unrelated post state.
• Diagnostic logs are empty, temporary resources were removed, and root diff/lint/unit/coverage/package/localdev verification passed.
• PR Complete the minimal 1.0 API additions #33 passed final protected CI run 34543321838, merged as 48b2923, and post-merge CI run 34579837783 passed all five jobs. T11 is completed.