add autocompletion, hover, and database linting (#1, #24, #25, #31)

add schema-aware LSP: config file, schema cache, and database-validat…

…ed diagnostics (#4, #7, #23, #31)

add semantic tokens for enhanced SQL syntax highlighting (#22)

adopt shared toba/lsp module and server harness (#27, #28)

initial project setup with SQL validation, release workflow, and issu…

…e tracking