feat: emotive animations + anime speed lines — hit flinch, dance emote (B)

- SkinnedPlayerModel: generic play_oneshot() (generalizes the Land lock),
  Hit and Dance in the clip table (Dance loops), restartable clips
- Hit flinch: victims visibly react on every peer's screen via the existing
  damage broadcast — no new RPC
- Dance emote on B: toggles while grounded and idle, breaks on any movement;
  synced to remotes via synced_is_dancing (all three spawner configs)
- Anime radial speed-lines overlay (canvas shader): fades in past ~1.2x walk
  speed, spikes on dash, widescreen-corrected clear center
- New input action 'emote' (B) in project.godot

11/11 FSM tests, spawn smoke 0 failures.

Co-Authored-By: Claude Fable 5 <[email protected]>

assets/shaders/speed_lines.gdshader

@@ -0,0 +1,38 @@
+shader_type canvas_item;
+
+// Anime-style radial speed lines. Fullscreen ColorRect overlay; `intensity`
+// (0..1) is driven by the player controller from horizontal speed + dash.
+// Lines live at the screen edges and jitter inward, center stays clear.
+
+uniform float intensity : hint_range(0.0, 1.0) = 0.0;
+uniform vec4 line_color : source_color = vec4(1.0, 1.0, 1.0, 1.0);
+
+float hash(float n) {
+	return fract(sin(n * 4310.17) * 43758.5453);
+}
+
+void fragment() {
+	vec2 uv = UV - vec2(0.5);
+	uv.x *= 1.6; // widescreen: keep the clear zone round-ish
+	float dist = length(uv);
+	float ang = atan(uv.y, uv.x);
+
+	// Quantize the circle into spokes; each spoke gets a stable random phase.
+	float spokes = 90.0;
+	float id = floor((ang / 6.2831853 + 0.5) * spokes);
+	float rnd = hash(id);
+
+	// Only some spokes draw, and they flicker over time.
+	float alive = step(0.55, fract(rnd + floor(TIME * 9.0) * 0.13));
+
+	// Thin line across the spoke's angular width.
+	float local = fract((ang / 6.2831853 + 0.5) * spokes);
+	float line = smoothstep(0.5, 0.05, abs(local - 0.5)) ;
+
+	// Radial extent: start further out for weak intensity, reach inward as it grows.
+	float start = mix(0.62, 0.34, intensity) + rnd * 0.12;
+	float mask = smoothstep(start, start + 0.25, dist);
+
+	float a = intensity * alive * line * mask;
+	COLOR = vec4(line_color.rgb, a * line_color.a * 0.55);
+}