Olivine style guide

Each guideline includes 'bad' and 'good' snippets, such as in the Tables section showing constructor syntax vs. property assignment, making rules easy to understand and apply.

Addresses Lua-specific quirks like nil handling in tables with an 'n' property recommendation and early validation in functions, based on practical scenarios from the README.

Provides specific advice on using the busted framework and organizing test files in a /spec folder, as detailed in the Testing section with example structures.

Focuses on uniform conventions without stylistic arguments, as stated in the philosophy, helping teams avoid subjective conflicts and maintain predictable code.