AtlasSpigot 26.2 - v10 (full re-verification, one real regression caught and fixed)

This release is a full re-verification pass, not just another single toggle - treating this as the milestone it's meant to be.

Did a complete fresh deployment exactly as the README instructs (not a shortcut test): booted via start.sh itself (not raw java -jar), read the entire log line by line instead of grepping for expected strings only, and confirmed a simulated client can actually complete the login handshake end to end (UUID assigned server-side).

That full read caught something real: optimize-entity-activation (enabled since v8) prints "[LeafConfig] You have following experimental module(s) enabled" on boot - Leaf's own source tags that field @experimental, an explicit signal from the maintainers that they don't consider it fully battle-tested, independent of how clean the diff looked when I first checked it. No open bug reports either way, but that's exactly the same category of caution already applied to parallel-world-ticking and sleeping-block-entity - just missed here until this pass. Reverted to false.

Re-verified after reverting: clean boot, no warnings besides the expected offline-mode notice (test-only), correct branding, successful simulated login.

Same jar as v9 (config-only change) - see README for the full breakdown, including this correction documented in the "deliberately not enabled" section rather than quietly dropped.