chore: tune fllnn-21-3 config and clean repo artifacts

- minor README fix

docs(readme,landing): improve navigation and add advanced examples

- added docs/landing site

- fixed README.md

- rewritten CLAUDE.md

- fixed README.md termins

refactor(playground): store mng temp files under outputs

chore: expand gitignore and update flashcards database

- added demo examples for MANGO src/playground

feat(cli): add visualize model option and richer errors

fix(types): align mypy config and shape protocol checks

docs(spec): add detailed plan for Python codegen builder

feat(codegen): support custom mango library module imports

refactor: move codegen builder and include mango_lsp in builds

chore: add hatch build setup and editor package metadata

feat(editor): add VS Code extension and Mango LSP server

docs(plan): mark ONNX export and REPL done in phase 3.3

feat: add ONNX export options and simplify demo app

feat(visualize): support input-shape and auto shape inference

docs(plan): mark Model Zoo milestone as completed