port(vscode-extension): rewrite extension.ts as extension.affine (affinescript#64)

[hyperpolymath]

Summary

• Ports vscode-extension/src/extension.ts (the only TypeScript file in this repo's VS Code extension) to AffineScript per the language-policy migration target (RS/TS/JS → AffineScript → typed-wasm).
• Closes the my-lang side of affinescript#64; the unblock condition affinescript#35 (Node-target codegen + stdlib/Vscode.affine + stdlib/VscodeLanguageClient.affine) has landed.
• Same pattern as the affinescript-side pilot port in affinescript#63, applied to this sibling repo.

What changed

File	Status	Purpose
vscode-extension/src/extension.affine	new	AffineScript source-of-truth. Ports activate, deactivate, the three command handlers (my-lang.run, my-lang.build, my-lang.test), and LSP startup.
vscode-extension/src/affine-vscode-adapter.cjs	new	Vendored JS-side adapter — copy of affinescript:packages/affine-vscode/mod.js in CJS form. Maps each extern fn in the bindings to a real vscode / vscode-languageclient/node call. Vendored because the upstream adapter isn't yet published as an npm package.
vscode-extension/src/index.cjs	new	Runtime entry point. Requires the compiled wasm shim, installs extraImports on it from the vendored adapter, then re-exports activate / deactivate. This is what VS Code's extension host loads (main in package.json points here).
vscode-extension/out/extension.cjs	new	Generated by npm run compile → affinescript compile src/extension.affine -o out/extension.cjs. Committed so the extension can be installed without the AffineScript toolchain on PATH.
vscode-extension/package.json	modified	main → ./src/index.cjs; compile invokes affinescript compile; TS devDeps (@types/*, typescript) dropped; version 0.2.0 → 0.3.0 to flag the rewrite.
vscode-extension/src/extension.ts	deleted	Replaced.
vscode-extension/tsconfig.json	deleted	No TypeScript to compile.

Acceptance criteria (from affinescript#64)

• affinescript#35 has landed.
• Port vscode-extension/src/extension.ts → .affine.
• Activation verified via shim.activate (registers the ExtensionContext as an opaque handle, wires bindings before instantiating wasm).
• Command registration verified — my-lang.run, my-lang.build, my-lang.test registered via Vscode::registerCommand with wasm-table indices 0, 1, 2 (order matches handler declarations in extension.affine).
• LSP wiring verified — VscodeLanguageClient::newLanguageClient + languageClientStart, using the my-lsp binary resolved from the my-lang.lsp.path configuration.
• Clean disposal verified — shim.deactivate exported; command disposables are pushed to ctx.subscriptions so the host releases them at extension unload. (Matches the affinescript pilot's intentional best-effort LSP stop.)

Known small degradations vs. the original .ts

These are acceptable for the first cut; they can be tightened once the affinescript binding surface grows (tracked in affinescript#64 follow-ups):

1. my-lang.test no longer cds into workspaceFolders[0]. The current Vscode.affine binding set has no workspaceFolders accessor. VS Code's default terminal cwd is the first workspace folder anyway, so single-root projects see the same behaviour; multi-root projects lose the explicit targeting.
2. LSP documentSelector is { scheme: "file" } (any file) rather than { scheme: "file", language: "my" }. The vendored adapter mirrors the upstream default; the LSP itself filters by file content / extension.
3. synchronize.fileEvents for the **/*.my glob is not wired — the LSP loses the workspace-side file-watcher feedback loop but still functions for open-document interactions.

Note on the TS-exemption table

affinescript#64 lists this acceptance bullet:

Each sibling repo updates its TS-exemption table to drop the ported entry.

The exemption row for vscode-extension/src/extension.ts lives on branch feat/stdlib-fs-env-format, not yet merged to main. On main there is no TS-exemption table to update; when that feature branch lands, the row for this file should be dropped at the same time.

Test plan

• npm run compile succeeds with the AffineScript toolchain on PATH (or AFFINESCRIPT_STDLIB env var pointing at affinescript/stdlib).
• Install the extension into VS Code (e.g. via vsce package + code --install-extension my-lang-0.3.0.vsix).
• Open a .my file — extension activates (onLanguage:my); console shows "My Language extension activated".
• Cmd/Ctrl+Shift+P → My: Run File — opens a terminal named My Language, runs my run "<path>".
• My: Build Binary — runs my build "<path>" -o "<path without .my>".
• My: Run Tests — opens terminal My Language Tests, runs my-test.
• If my-lsp is on PATH, LSP starts (hover / completion / diagnostics work). If not, the extension still activates; LSP wiring fails silently as in the original.
• Reload window — deactivate runs cleanly, no disposable leaks.

🤖 Generated with Claude Code