Prebuilt Godot documentation indexes

Prebuilt search indexes for the Godot documentation, one asset set per
engine version.

Most recent build: Godot 4.7, from godot-docs 4b404adc7c3a4eb7b5392bed8833cdc52f164338 and godot
f6ab5db28b9d989a3ae710d57410a123cf0e4b23.

Each *.manifest.json records exactly what its own index was built from.
Installed with godot-docs-mcp sync; nothing here needs downloading by hand.