fix(movement): jump works locally (airborne velocity preserved)

Two fixes for jump physics:
- Skip ground-snap when velocity Z > 0 (prevents immediate re-landing
  at high framerates where per-frame Z delta < 0.05 snap threshold)
- Guard apply_current_movement velocity write behind OnWalkable check
  (prevents MotionInterpreter.DoMotion from zeroing jump velocity on
  every frame while airborne)
- Guard PlayerMovementController velocity replacement behind OnWalkable
  (preserves momentum during airborne flight)

Jump works locally but server packet not yet sent (BUG-002).
Facing direction mismatch logged as BUG-003.
RunRate not verified as BUG-004.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/bugs.md

@@ -18,6 +18,37 @@ the "Fixed" section with the commit hash that resolved it.
   or the CreaturePalette pipeline in `InstancedMeshRenderer`.
 - **Phase:** Unassigned (investigate after rendering rebuild Step 5).
 
+### BUG-002: Jump not visible from retail client
+- **Observed:** 2026-04-14
+- **Description:** Jump works locally (player rises and falls) but no
+  jump packet is sent to the server. Other clients don't see the jump.
+- **Repro:** Jump in acdream, observe from retail client — no jump visible.
+- **Likely area:** GameWindow.cs jump packet sending (currently a TODO
+  Console.WriteLine). Need to research jump packet format from holtburger.
+- **Phase:** B.2 (movement completion)
+
+### BUG-003: Facing direction mismatch with server
+- **Observed:** 2026-04-14
+- **Description:** Character facing direction in acdream doesn't match
+  what other clients see. Our quaternion convention for outbound
+  MoveToState/AutonomousPosition packets is wrong.
+  AC convention: heading 0 = West, 90 = North, 180 = East, 270 = South.
+  Our convention: Yaw 0 = +X (East in AC terms). The wireRot quaternion
+  needs to use holtburger's `from_heading` formula:
+  `theta = (450 - degrees).to_radians()`, `w=cos(theta/2)`, `z=sin(theta/2)`.
+- **Repro:** Walk in acdream, observe from retail client — character faces
+  wrong direction.
+- **Likely area:** GameWindow.cs wireRot computation (line ~1899).
+- **Phase:** B.2 (movement completion)
+
+### BUG-004: Run speed not verified working
+- **Observed:** 2026-04-14
+- **Description:** RunRate wiring exists (Task 1) but user reported no
+  speed change. Either the server's UpdateMotion ForwardSpeed isn't being
+  received, or it's not propagating to the velocity computation. Need to
+  add diagnostic logging to verify the UpdateMotion path fires.
+- **Phase:** B.2 (movement completion)
+
 ---
 
 ## Fixed