Fix playtest AI behavior and defer stabilizer regeneration

[xefensor]

Summary

Fix the AI and Aender stability issues found during the 2026-08-23 short playtest:

• keep urgent ground-mob flight on dry routes when the mob starts on land
• stop Creepers and the full Retold Undead faction from fleeing an active Creeper fuse
• keep Village Defenders neutral to idle Piglins and Endermen while preserving real retaliation
• remove Aender Stabilizer protection immediately but defer terrain replacement until each released chunk has no client watchers

The stabilizer handoff uses a persistent, save-compatible deferred chunk-reality state so watched terrain and player edits cannot disappear before the existing paced blank/regeneration queues own the work.

Player or developer impact

Animals no longer choose water-crossing Retold flee routes from land. Creepers and Undead hold their ground near an ignited Creeper. Iron Golems no longer start unsolicited fights with exposed Piglins or Endermen. Breaking an Aender Stabilizer removes its forcefield immediately, but watched released terrain stays intact until its last watcher leaves.

The nearby Panda jump noted during the playtest is vanilla baby-sneeze behavior and is intentionally unchanged. RetoldBlocks registration is unchanged because the affected behavior belongs to AI targeting/movement and Aender stability ownership.

Validation

• ./gradlew build
• ./gradlew runGameTestServer, when relevant
• Focused in-game testing, when relevant
• Dedicated-server or multiplayer testing, when relevant

Passed:

• ./gradlew build (JUnit, PMD, assembly)
• retold:land_mob_flee_paths_do_not_enter_water — 1/1
• retold:ignited_creeper_causes_delayed_flight_except_creepers_and_undead — 1/1
• retold:village_defenders_ignore_neutral_piglins_and_endermen_until_attacked — 1/1
• retold:aender_stabilizer_release_preserves_terrain_until_eligible — 1/1
• retold:aender_stability_round_trip_preserves_overlap_counts — 1/1
• retold:aender_reality_regenerates_only_volatile_chunks — 1/1
• AenderDeferredReleasePolicyTest — 4/4
• retold:mob_tps_cow — all five phases below 50 ms/tick, 5.806 ms/tick peak
• retold:mob_tps_wolf — all five phases below 50 ms/tick, 5.476 ms/tick peak

Not performed: subjective client checks and real two-player Aender watch/departure/save-restart testing. The GameTest server does not load the custom Aender dimension. Natural mixed-terrain fleeing, multi-species fuse reactions, and village encounters still need developer in-game confirmation.

AI assistance

• I reviewed and understand all submitted changes, including AI-assisted output.

Codex traced the owning AI/stability paths, implemented the changes, added tests, updated documentation, and ran the listed validation. The developer supplied the playtest reports and explicitly confirmed the deferred stabilizer-release contract.

Documentation and release notes

• Updated CHANGELOG.md for player-facing or notable technical changes
• Updated README or system documentation when behavior or architecture changed
• Added or updated tests where practical

Updated implementation status, AI architecture, Aender architecture, risks/issues, TPS records, and release notes.

Visual evidence

Not included. No creative assets or UI were changed, and real Aender multiplayer presentation remains a developer verification item.

Licensing

• I have the right to contribute every included file.
• Code and non-asset contributions are provided under LICENSE-CODE.md.
• No creative-asset contributions are included in this PR.