[M1-S1] Walk and run with weight #27

User story

As a player, I want the hero to walk and break into a run when I hold a direction, so that moving feels like a person in a heavy poncho, not a cursor.

Acceptance criteria

• About 3.5 m/s walking, 6 m/s running after 0.4 s held (1 m ≈ 43 px)
• Short acceleration and deceleration
• Faces the move direction; keyboard (A/D, arrows) and gamepad (stick, D-pad)

Design and references

02 – Movement and controls.

Dependencies

Blocked by the scaffold. Suggested owner: Vatsal (player and combat code).

Verification

Play on the preview with keyboard and gamepad; speeds measured with the debug overlay.