Fire PLAYER_STARTED_MOVING for both-mouse-button run

Holding both mouse buttons to run forward never fired
PLAYER_STARTED_MOVING. Ghidra trace of the input button handler
(FUN_00514840) shows that gesture drives the forward move directly at
the movement layer (FUN_005103e0) and explicitly clears the autorun
bit on the both-button press — so it sets none of the
INPUT_FLAGS_MOVING_ANY bits the mover-detection reads. (The Offsets.h
comment claiming the both-button combo sets autorun was wrong;
corrected.)

Detect it from the bit combo instead: both INPUT_FLAG_MOUSELOOK (RMB)
and INPUT_FLAG_FREE_LOOK (LMB) held means the engine is mouse-steering
the character forward. ORed into `moving`. Composes cleanly with the
TURNING/LOOKING latches (unchanged).

src/Offsets.h

@@ -3379,13 +3379,19 @@ enum Offsets {
     // Bits 4-7 — WASD movement-key state. Each `MoveForwardStart`
     // / `StrafeLeftStart` / etc. pushes one of these as the bit
     // mask into the engine's button-press handler. Bit `0x1000` is
-    // the autorun-active flag (set by `ToggleAutoRun` and the
-    // both-mouse-buttons combo). `INPUT_FLAGS_MOVING_ANY` is the
-    // engine's own "is the user currently inputting translational
-    // movement" mask, used to drive `PLAYER_STARTED_MOVING` —
-    // matches modern's "STOPPED fires on key release, even
-    // mid-air" semantics because no physics/airborne bit is
-    // involved.
+    // the autorun-active flag (set by `ToggleAutoRun`).
+    // `INPUT_FLAGS_MOVING_ANY` is the engine's own "is the user
+    // currently inputting translational movement via keys/autorun"
+    // mask, used to drive `PLAYER_STARTED_MOVING` — matches modern's
+    // "STOPPED fires on key release, even mid-air" semantics because
+    // no physics/airborne bit is involved.
+    //
+    // NOTE: the "hold both mouse buttons to run forward" gesture is
+    // NOT in this mask. The button handler (`FUN_00514840`) drives
+    // that forward move directly via `FUN_005103e0` and explicitly
+    // *clears* the autorun bit when both buttons go down. Detect it
+    // from `INPUT_FLAG_MOUSELOOK & INPUT_FLAG_FREE_LOOK` both held
+    // instead — see `Player::InputEvents`.
     INPUT_FLAG_MOVE_FORWARD = 0x10,
     INPUT_FLAG_MOVE_BACKWARD = 0x20,
     INPUT_FLAG_STRAFE_LEFT = 0x40,

src/player/InputEvents.cpp

@@ -111,10 +111,21 @@ void OnWorldTick() {
 
     const uint32_t flags = *reinterpret_cast<const uint32_t *>(
         ctrl + Offsets::OFF_UI_INPUT_FLAGS);
-    const bool moving        = (flags & Offsets::INPUT_FLAGS_MOVING_ANY) != 0;
     const bool freeLookHeld  = (flags & Offsets::INPUT_FLAG_FREE_LOOK) != 0;
     const bool mouselookHeld = (flags & Offsets::INPUT_FLAG_MOUSELOOK) != 0;
 
+    // MOVING — translational input. The WASD / autorun keys set the
+    // INPUT_FLAGS_MOVING_ANY bits directly. The "hold both mouse
+    // buttons to run forward" gesture does NOT: the engine drives that
+    // forward move at the movement layer (FUN_005103e0 from the button
+    // handler) and actually *clears* the autorun bit on the both-button
+    // press, so no MOVING_ANY bit is ever set. Detect it from the
+    // bit combo instead — both mouselook (RMB) and free-look (LMB)
+    // held means the engine is mouse-steering the character forward.
+    const bool mouseSteerMoving = mouselookHeld && freeLookHeld;
+    const bool moving =
+        (flags & Offsets::INPUT_FLAGS_MOVING_ANY) != 0 || mouseSteerMoving;
+
     // TURNING — latched bit-AND-rotation signal:
     //   STARTED fires when mouselook bit is held AND the body yaw
     //     changes (the first actual drag after pressing RMB).