docs(affine-vscode): align adapter docs with --vscode-extension (issue #105)

The README and mod.js still described the pre-#105 manual hookup and
referred to the hook as `_extraImports`. The codegen shim uses
`extraImports` and #105 now emits the wiring inline.

- Document `--vscode-extension` (and the adapter / no-lc sub-flags) as
  the recommended path; keep a corrected manual fallback.
- Fix the hook name `_extraImports` -> `extraImports`.
- Fix the manual example's third argument: the adapter expects the .cjs
  shim module (it reads `_registerHandle` / `_instance` off it), not a
  `() => instance` thunk or a bare WebAssembly.Instance.

https://claude.ai/code/session_01FkzAgzpZFSGxzorVNZ9FUF

Author: claude

packages/affine-vscode/README.adoc

@@ -8,28 +8,41 @@ deliverable.
 
 == Usage
 
-In your AffineScript-authored VS Code extension's CJS entry point, after
-loading the `.cjs` produced by `affinescript compile extension.affine
--o extension.cjs`, plug this adapter into the Wasm imports:
+=== Recommended: `--vscode-extension` (issue #105)
+
+Compile with the `--vscode-extension` flag and the generated `.cjs` is
+directly loadable as the extension's `main` — the adapter wiring is
+emitted inline, so there is no hand-written entry point to maintain:
+
+[source,sh]
+----
+affinescript compile src/extension.affine -o out/extension.cjs --vscode-extension
+----
+
+Point your extension's `package.json` `main` at the unmodified
+`out/extension.cjs` and list `@hyperpolymath/affine-vscode` in
+`dependencies`. Sub-flags: `--vscode-extension-adapter <specifier>`
+overrides the adapter `require()` target; `--vscode-extension-no-lc`
+omits the `vscode-languageclient/node` dependency.
+
+=== Manual wiring (fallback)
+
+If you cannot use the flag, set the shim's `extraImports` hook before the
+first `activate`/`deactivate` call so the extern fns resolve to live
+vscode APIs. Pass the shim module itself as the third argument — the
+adapter reads its handle table and `_instance` lazily:
 
 [source,javascript]
 ----
 const vscode = require("vscode");
 const lc = require("vscode-languageclient/node");
 const makeBindings = require("@hyperpolymath/affine-vscode");
 
-// The Node-CJS shim emitted by affinescript's compile -o *.cjs path lazily
-// instantiates the wasm. Patch its `_extraImports()` hook before the first
-// activate/deactivate call so the extern fns resolve to live vscode APIs.
-
-let instance;
-const adapter = require("./extension.cjs");
-const original = adapter._extraImports || (() => ({}));
-adapter._extraImports = () => makeBindings(vscode, lc, () => instance);
+const shim = require("./extension.cjs");
+shim.extraImports = () => makeBindings(vscode, lc, shim);
 
-// (Real wiring belongs in the codegen — Phase 3 will replace this manual
-// hookup with auto-generated glue once `extension.affine` is the source of
-// truth for the extension entry point.)
+exports.activate = shim.activate;
+exports.deactivate = shim.deactivate;
 ----
 
 == Surface

packages/affine-vscode/mod.js

@@ -3,18 +3,21 @@
 //
 // affine-vscode: JS-side adapter for stdlib/Vscode.affine + stdlib/VscodeLanguageClient.affine.
 //
-// Issue #35 Phase 2 deliverable. Plug this into your Node-CJS extension's
-// `_extraImports()` so each `extern fn` declared in the bindings resolves
-// to the right vscode API call.
+// Issue #35 Phase 2 deliverable. Resolves each `extern fn` declared in the
+// bindings to the right vscode API call.
 //
-// Usage from a hand-written .cjs (until Phase 3 automates the wiring):
+// Preferred wiring (issue #105): compile with `--vscode-extension` and the
+// generated .cjs installs `exports.extraImports` calling this adapter
+// automatically — no hand-written entry point.
 //
-//   const vscodeBindings = require("@hyperpolymath/affine-vscode")(
+// Manual wiring (fallback), from a hand-written .cjs:
+//
+//   const shim = require("./extension.cjs");
+//   shim.extraImports = () => require("@hyperpolymath/affine-vscode")(
 //     require("vscode"),
 //     require("vscode-languageclient/node"),
-//     instance,                         // WebAssembly.Instance, set after instantiate
+//     shim,                             // the .cjs shim module (hostShim)
 //   );
-//   // Pass vscodeBindings into the Wasm imports map under "env".
 //
 // The adapter maintains a per-process JS-side handle table keyed by Int
 // so opaque handles passed across the FFI boundary survive round-trips.