Fix current AzerothCore compatibility

[G-kylexy]

What changed

• synchronize PlayerUpdates.cpp with current AzerothCore while preserving the faction-free city behavior
• replace removed cinematic, combat, weather, and visibility APIs with their current equivalents
• update creature_template inserts for the current database schema
• make the entry checker independent of the creature identifier column name
• document the current-main database prerequisite and compatibility release

Root cause

The repository ships a full replacement copy of PlayerUpdates.cpp. That copy had fallen behind AzerothCore API changes, while the SQL still referenced fields removed from the current creature_template schema.

Validation

• compared PlayerUpdates.cpp with AzerothCore main at 9f66598caa0334aa5f2a00cd3aa1b917c10c3d98; the only intentional behavioral difference is the faction-free city block
• checked all SQL insert columns against the current AzerothCore base schemas
• verified all 83 SQL insert statements have matching column/value counts
• git diff --check passes

A full Windows server build was not available in this environment.

Fixes #27