Correct big-endian offboard state flag checks

docs/OFFBOARD_STATE_FLAGS.md

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+# Off-board state flag correction
+
+The user reported jumps immediately playing a landing animation, repeated
+landing animations and rising motion after walking off a ledge. The preceding
+run's stderr contained no airborne bail report; this alone does not establish
+whether the airborne state was entered.
+
+Static evidence: TU3 dump `default_82000000_011B0000.bin`, SHA-256
+`f4aa113eb541bfba03dbc108cf5ab43f58c965b20fa3b82f9c40938a0ad841c4`.
+The generated instruction listing for `82D8ADE8` contains:
+
+- `82D8B8D4`: `lhz r11,2484(r4)`, followed by a low-bit test.
+- `82D8B490` and `82D8B5F0`: `lbz r11,2484(r4)`, followed by a low-bit test.
+
+On this big-endian target these test full-word masks `0x00010000` and
+`0x01000000`, respectively. The port incorrectly used `0x00000001` for all
+three. Bit16 is published from Offboard328, the airborne continuation flag;
+bit0 is a separate animation attribute. BipedAir therefore incorrectly returned
+to BipedGround while its airborne flag was still set.
+
+Corrected all three masks. Repeated premature ground entry is a plausible
+cause of the reported animation loop; gameplay confirmation remains with the
+user. Build only, no tests run. Bounded bail diagnostics also cover BipedGround
+so any remaining turning-related failure can be captured.