Fix missing projectile and grenade contact explosion effects in Boot config

[h5kk]

Problem

In Boot's Max FPS config, projectile and grenade contact explosions (such as Yamato's alternate fire right-click burst) do not render contact explosion effects upon impacting surfaces or enemies.

Root Cause

Several cvars in Boot's config aggressively suppress impact and particle rendering:

1. cl_impacteffects "0" and citadel_per_weapon_per_surface_impact_effects "false": Suppressed all surface impact effects.
2. particle_cluster_nodraw "1" and particle_cluster_use_collision_hulls "false": Skipped drawing particle clusters and disabled collision hulls for clusters.
3. r_particle_max_detail_level "0": Culled ability and explosion particles that require detail level >= 1 (Spooky's config already sets this to "1").
4. cl_phys_enabled "false": Disabled client-side physics simulation, preventing projectile collision/contact events from properly dispatching on the client.
5. r_particle_allowprerender "false": Skipped pre-rendering required for instant single-frame explosion bursts.
6. cl_particle_sim_fallback_threshold_ms "0" and aggressive multipliers: Immediately forced spawned particle systems into degraded/empty fallbacks.

Solution

• Re-enabled citadel_per_weapon_per_surface_impact_effects "true" and cl_impacteffects "1".
• Reset particle_cluster_nodraw "0" and particle_cluster_use_collision_hulls "true".
• Set r_particle_max_detail_level "1" (matching Spooky's config).
• Set cl_phys_enabled "true" and r_particle_allowprerender "true".
• Commented out the 0ms fallback simulation thresholds.

Verification

Tested in-game: Yamato's right-click burst now properly renders its contact explosion effect on surfaces and targets, while maintaining all other FPS optimizations (shadows, lighting, cloth, models, audio, HUD).