PHAYRIOSIS REBORN CONTINUED — PHASE 7C DIFFICULTY PRESETS — 0.0.20

PURPOSE
Adds world-specific infection difficulty presets while preserving Phayriosis progression/evolution ratios and the accepted meteor/Create World systems.

PRESETS
Easy:
- infected max health: 0.50x
- infected attack damage: 0.50x
- infection progression/spread pace: 0.50x

Normal:
- 1.00x health, damage, and infection pace
- exact baseline Phayriosis behavior

Advanced:
- infected max health: 1.40x
- infected attack damage: 1.40x
- infection progression/spread pace: 1.25x

Hard:
- infected max health: 1.80x
- infected attack damage: 1.70x
- infection progression/spread pace: 1.35x

Nightmare:
- infected max health: 2.20x
- infected attack damage: 2.00x
- infection progression/spread pace: 1.50x
- legacy Phayriosis nightmaremode behavior remains enabled

IMPLEMENTATION RULES
- Difficulty is persisted per-world in PhayriosisWorldSettings.infectionDifficultyMode.
- Create World pending profile stores the selected preset and applies it once to a fresh world.
- Fixed UUID AttributeModifiers make health/damage scaling idempotent; chunk reloads, rejoins, or dimension changes cannot stack the modifiers repeatedly.
- Only Phayriosis living-entity classes are difficulty-scaled; unrelated vanilla/mod mobs are untouched.
- Health percentage is preserved when a modifier is installed.

EVOLUTION SAFETY
Health-gated evolution MUST scale with difficulty-adjusted health. Do not restore fixed 100/150 comparisons.
- Bulb original ratio: 20 base HP -> 100 evolution HP = 5x. Effective threshold = 100 * health multiplier.
- Dome original ratio: 100 base HP -> 150 evolution HP = 1.5x. Effective threshold = 150 * health multiplier.
This prevents Easy from evolving too quickly and high difficulties from making evolution disproportionately easy.

INFECTION PROGRESSION
- Phase point awards are left intact. Instead, all seven PhaseCalculator thresholds are scaled by normalThreshold / infectionPaceMultiplier.
- Physical infection spread rolls in BlockspreadspeedconditionProcedure and the four primary Phayrilesh mound spread gates are scaled by the same pace multiplier.
- Existing manual Base Spread Setting remains separate; the difficulty pace is layered on top.

METEOR INTERACTIONS
- The meteor still forces Phase 4 immediately on successful launch. Its 10,000-point Phase-4 floor now goes through requiredPoints(), so Easy/Advanced/Hard/Nightmare cannot immediately recalculate to a different phase.
- The meteor Nucleus still has a 500 HP base. Difficulty may scale its final max HP; after the base is set, current health is filled to the resulting max.

PRESERVATION
- SRP-style Create World button lifecycle remains unchanged.
- Meteor flight entity, chunk loader, renderer, flight audio, shockwave, terrain, and accepted world-event behavior are not otherwise retuned in this release.

TEST PRIORITIES
1. Create one world per preset and verify representative infected health/damage.
2. Verify Bulb and Dome evolution remains proportional rather than instant/impossible.
3. Verify phase progression and block spread pace differ as intended.
4. Verify Nightmare still enables the legacy nightmare behavior.
5. Verify meteor launch still forces Phase 4 on every preset and the core Nucleus spawns fully healed.
