Editor: move AuthorsSelect init side effects to useEffect

[dknauss]

What this does

Moves initial author-selection setup out of render and into useEffect.

What this fixes

Prevents render-time state updates and render-time async fetch work in AuthorsSelect, which can lead to repeated initialization and unstable editor behavior.

What this changes

• moves initial selected-author hydration into useEffect
• adds a one-time initialization guard
• moves async preload fetch into the effect lifecycle
• adds a cancellation guard so stale async completion does not update state

Why

The current component mutates state and starts async work while rendering. React components should keep render pure and perform this setup in effects.

Scope

This PR is intentionally narrow with only front-end concerns.

Included:

• src/components/AuthorsSelect.tsx

Not included:

• broader frontend modernization
• react-select upgrade work
• hook migration
• accessibility/UI follow-up changes

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Delay initialization until author IDs are available

This unconditional hasInitializedSelection.current = true runs even when currentAuthorIDs is not yet available (for example, initially undefined/empty before editor data finishes loading), so later effect executions immediately return at the top guard and never hydrate selection from preload or API. In that delayed-load scenario the selector remains empty despite the post having authors, which is a regression from the previous logic that retried initialization once IDs appeared.

Useful? React with 👍 / 👎.

[dknauss]

Interesting catch! A little over-zealous since setting hasInitializedSelection.current = true at line 105 (the final fallback at the bottom of the effect) means that if currentAuthorIDs is initially undefined/empty, the guard at the top will prevent later hydration when IDs arrive.

But — there's a possible edge case: if currentAuthorIDs is initially [] (empty array, not undefined), the effect falls through to line 105, sets the ref to true, and then when real IDs arrive, the guard blocks re-initialization. That's a real (if unlikely) race condition depending on how the block editor hydrates the store.

The fix is setting the ref to true inside the two branches that actually initialize (preload match and API fetch), removing line 105 entirely.

Fixed in c7a772e. The fallback guard is removed so the effect re-runs until real data arrives.