Combat feel pass: enemy hit-flash, melee connect cue, kill pop, gamepad rumble, footsteps, damage-number tiering

Implements the "what's missing" feel backlog from the combat overhaul investigation (wf_c6c87dc5-9c3). All
client-only, observe-only (PresentationSystemGroup), no sim/netcode change, rollback-safe; new FeelConfig knobs
default-stamped on play-enter.

- ENEMY HIT-FLASH (#1 missing): on the enemy Health-decrease edge, a bright body-scaled particle puff in the
  previously-unused FeelConfig.HitFlashColor (via a new EmitColored helper using per-emit startColor) -- the staple
  "I connected" read. (A true material body-flash needs an AnimatedLitShader emission property + Entities Graphics
  MaterialProperty; the puff is the asset-free version.)
- MELEE CONNECT-vs-WHIFF: on the local swing, a client-side MeleeConeMath.InCone overlap over the cached enemy
  snapshot -> immediate connect read (brightens the slash arc, hit-spark at the nearest enemy, a meaty low "thunk"
  SFX, extra FOV punch) before the authoritative server spark arrives. Whiffs stay dim.
- KILL POP: a colored flash burst + rumble on enemy death (on top of the existing burst/shake/FOV).
- GAMEPAD RUMBLE: new RumbleUtil (auto-stopping pulse, gamepad-only, stops on focus-loss, reset on play-enter)
  pulsed on local hit-taken / hit-dealt / kill, gated on AimPresentation.Scheme==Gamepad.
- FOOTSTEPS: edge-detect local locomotion from the position delta -> soft step SFX at a cadence while moving.
- DAMAGE-NUMBER TIERING: SpawnNumber scales font + life by hit magnitude (vs HitStopRefDamage) so heavy hits read.

390/390 EditMode, clean compile + Play (no exceptions; per-frame footstep/rumble-tick paths verified). On-screen
feel is the operator's eyes. Deferred (focused follow-ups): true material body hit-flash (ShaderGraph), co-op
remote-swing rendering, near-impact telegraph beep (clip reserved).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/_Project/Scripts/Client/Presentation/RumbleUtil.cs.meta

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