Adds major Semantic Layer functionality with relation definitions for Cubes

What's Changed

• fix: replace DBC V views with VX views for row-level access control (issue #334) by @dtehan-td in #337
• chore: upgrade starlette to >=1.3.1 by @dtehan-td in #338
• docs: refresh main README with outcome-focused layout and recent features by @dtehan-td in #339
• docs: add inline module documentation links to README by @dtehan-td in #340
• docs: fix Custom Logic row formatting in What You Can Do table by @dtehan-td in #341
• Improve LLM routing clarity for dba, sec, qlty, plot modules (issues #344-347) by @dtehan-td in #349
• Reorganize test structure: move integration tests into subdirectory by @dtehan-td in #350
• chore: remove temporary seed and DDL extraction files by @dtehan-td in #351
• chore: upgrade langsmith to >=0.8.18 by @dtehan-td in #352
• Clean up eval results and update gitignore by @dtehan-td in #353
• docs: add eval_test suite to tests README by @dtehan-td in #354
• Fix/skill top param pattern by @remi-td in #355* Semantic layer relations by @remi-td in #358
• Semantic layer doc by @remi-td in #359

Full Changelog: v0.2.4...v0.2.5