Introduce a game-thread-only, read-only diagnostic helper to probe local player animation graph variables and (optionally) numeric cache IDs. Adds F4TLocalAnimationGraphDebug.h/cpp with UpdateLocalPlayerAnimationGraphDebug(...) and wires a call into plugin/src/main.cpp immediately after GetPlayerMovementState. The helper probes curated variable names via CommonLibF4 read-only APIs, logs availability/changes, and includes a disabled-by-default numeric cache ID scan (kEnableLocalPlayerAnimationGraphCacheIdReadOnlyDebug = false) due to a reported crash during testing. Update also adds extensive dev-log documentation (docs/dev-log.md) describing behavior, testing notes, and rollback instructions. Build succeeded; manual F4SE in-game verification remains pending.
