Rook attack/mobility: bitboard rewrite; backport bounded x-ray chaining to bishop

_EvalRook's mobility ray-walk and RMobCaseTable switch replaced with
_RookAttacksBB(c, pos->bbOccupied) plus bitboard masks, same technique
as knight/bishop. Adds pos->bbRookAttacks[2]/bbRookXrayAttacks[2],
first contributors alongside bbMinorAttacks/bbMinorXrayAttacks.
Connected-rook bonus and x-ray population derived from the attack
bitboard instead of a per-square dispatch.

Unlike bishop's single-hop x-ray simplification, rook's x-ray
population uses a bounded chain-following loop (recompute with the
newly-found blocker excluded, repeat until no new x-ray-worthy
terminal appears): checked frequency first (board_representation/
EVAL.md), and 14% of the curated-suite positions have a genuine
2+-deep rook/queen battery on some ray, far more common than bishop's
~1% -- a one-hop approximation here would be a real fidelity loss, not
a negligible one. The stashed first bitboard-eval attempt (git
stash@{1}) had already solved this correctly by walking blocker-to-
blocker via bit-scan; this reproduces the same unbounded behavior via
repeated magic-lookup recomputation, cheap because the loop only
iterates again when an actual chained battery exists.

Backported the same bounded-chain fix to bishop's x-ray population
(previously single-hop only) for consistency, now that it's known
cheap and mechanically identical -- bishop's own battery rate is much
lower (~1%) so this mostly just removes an intentional divergence
rather than fixing an active problem.

Also fixes two real correctness gaps this conversion would otherwise
have introduced silently (same failure mode as pawn's earlier
conversion, EVAL.md's progress log): rook no longer writes ROOK_BIT/
ROOK_XRAY_BIT into the old per-square bvAttacks structure, but
_WhoControlsSquareFast and queen's mobility unsafe-check both still
read those bits directly. Added _IsSquareAttackedByRook/
_IsSquareXrayedByRook (same transitional-helper, DEBUG-cross-checked
pattern as the minor-piece helpers) and updated both call sites.

Verified via precommit_check.sh (self-test + DEBUG smoke test) after
each step.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01XxmVi2sTMwpPp4i6WYFjan

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