ML flavor front end, formatter, effects, modules, and docs/website overhaul

[MelbourneDeveloper]

TLDR

Adds a second ML (offside/curry-by-default) surface to Osprey — parser, lexer, lowering, formatter, LSP, and VSCode support — proven byte-for-byte equivalent to the Default flavor, alongside a full spec/docs/website overhaul and a browser WebAssembly SQL demo.

Details

ML flavor frontend (crates/osprey-syntax/src/ml/) — a complete indentation-delimited, curry-by-default front end that lowers to the same AST as the Default flavor:

• lexer.rs / token.rs — offside-rule layout lexer (INDENT/DEDENT, newline-terminated strings).
• parser.rs / cst.rs — ML grammar: whitespace application (f x), \x => e lambdas, := mutation, = binding, layout blocks — no fn/let/braces.
• lower.rs (1730 LOC) — lowers the ML CST to the shared AST.
• crates/osprey-syntax/src/default/ — the existing brace-flavor parser moved under default/ so the two surfaces sit side by side; strings.rs factored out as shared interpolation lexing.
• .osp → Default, .ospml → ML, selected by extension; a flavor marker conflict is a hard error.

Formatter (crates/osprey-fmt/ + osprey fmt) — new crate with brace (brace.rs) and layout (layout.rs) formatters plus a shared scanner; wired into the CLI as osprey fmt (stdin/dir-recursive/check/rewrite modes) and into make fmt.

Algebraic effects / first-class handlers — compiler/runtime/effects_runtime.c (+250) and osprey-codegen/src/effects.rs (+515) extend effect resumption and make handlers first-class values.

Modules & namespaces — spec 0025 plus supporting type-checker and lowering changes.

LSP / VSCode — osprey-lsp gains flavor-aware diagnostics/features; new osprey-ml.tmLanguage.json, ML snippets, and language-configuration-ml.json.

Website & docs — every website/src/spec/* chapter revised; new chapters 0023 Language Flavors, 0024 ML Flavor Syntax, 0025 Modules and Namespaces; mirrored under docs/specs/. /docs/ index gains an inline Flavors explainer (one language, two ways to write it). New /wasm/ page: an Osprey program compiled to wasm32-wasip1 seeds a real in-browser SQLite (sql.js) database with a tabbed query/add-data/source UI, and both the Osprey and SQL are Prism-highlighted (js/wasm-studio.js). Playground gains a Default⇄ML flavor toggle.

Examples — most examples/tested/* programs gain a byte-identical .ospml twin; several .osp files were de-annotated to lean on inference.

Cleanup note: this branch also carries scratchpad/ working files and */.claude/settings.local.json that should probably be dropped before merge.

How Do The Automated Tests Prove It Works?

make ci (lint + test + build) passes end-to-end, exit 0. Specific coverage:

• cross_flavor_ir_equiv.rs — every_ml_example_has_a_default_twin and ml_and_default_twins_emit_identical_ir compile each .ospml/.osp pair and assert the emitted LLVM IR is identical, proving the ML surface lowers to the same program.
• cross_flavor_equiv.rs — ml_multiparam_equals_default_explicit_curry / ml_uncurried_tuple_equals_default_multiparam pin ML currying semantics against the Default flavor.
• corpus.rs — default_examples_format_idempotently and ml_examples_format_idempotently prove osprey fmt is a fixpoint over the whole example corpus (format twice == format once).
• cli_e2e.rs — fmt_*, flavor_marker_conflict_exits_two, check_*, and llvm_emits_ir_and_rejects_ill_typed exercise the fmt/check/llvm CLI surface end-to-end including error exit codes.
• no_needless_main.rs — no_example_wraps_a_trivial_program_in_main enforces the style rule across examples.
• ml_coverage.rs (823 LOC) — parser/lowering unit coverage for the ML front end.
• Differential harness (diff_examples.sh / diff_wasm_examples.sh) — every .osp/.ospml in examples/tested/ runs and must match its .expectedoutput byte-for-byte.
• Website E2E (website/tests/interactions.spec.js) — wasm demo seeds a browser SQLite db and runs queries boots the wasm module, asserts #banner reaches "Database ready", the query tab auto-renders a result table with highlighted SQL tokens, the source tab shows highlighted Osprey, and adding a row then re-querying reflects the new data; playground flavor toggle swaps the sample between .osp and .ospml verifies the Default⇄ML toggle.
• VSCode extension suite — 78 passing, coverage 90.94% (≥89% threshold).