Simplify max-tile histogram counting in movefeed

[mmiermans]

Small readability cleanup in the move feed endpoint.

The max-tile statistics counter used a four-line isset/else block to increment per-tile counts. This replaces it with the null-coalescing operator so the intent (a histogram increment) reads in a single line, and switches the scoreStats accumulation from array_push() to the [] append shorthand for consistency with the rest of the file.

No behavior change — purely a refactor.

[github-actions]

🤖 Claude has reviewed this PR — expand after forming your own opinion

Clean, minimal refactor. Both changes are idiomatic PHP improvements.

Null-coalescing histogram increment (line 41) — Good. The ?? operator is the idiomatic way to express this in PHP 7+, and it correctly preserves the semantics of the original isset/else block.

$scoreStats[] shorthand (line 43) — Good. [] is preferred over array_push() for single-element appends (avoids function-call overhead and is the more common PHP idiom).

Minor note on consistency: The PR description mentions the [] change is "for consistency with the rest of the file," but the move-feed section below (lines 84-90) still uses array_push() throughout. This is fine as-is — those calls append to a different structure in a different logical block — but if you do want full consistency, those could be converted in a follow-up.

No security, performance, testing, or documentation concerns. The changes are behavior-preserving and the PR description accurately captures the intent.