Add hemx-lsp for stdio LSP diagnostics, completion, and hover while preserving HTML editor tooling for .heml files. Teach hemx-build to expose generated target and derive-known template context facts, including simple h-for locals, so editor help comes from build-owned facts instead of editor-only parsers. Wire VS Code/Cursor and Neovim documentation and extend the Workout exemplar with a real h-for plan loop for end-to-end proof.
req: diag/004
req: diag/005
req: diag/006
slhx agent