chore(ffi-linkage): post-stream polish — vscode keywords + vestigial param + extension metadata

Two post-stream follow-ups flagged in CHECKPOINT-EXTERN-EXPORT.md, plus a
reproducible vscode-extension packaging setup:

- parser: drop the vestigial `RuntimeClassPrefix.is_extern` field and
  `parseRuntimeClassDecl`'s `is_extern` param. Always false since the
  `#foreign` token was deleted; the postfix `extern`/`export` keyword is the
  sole reference-vs-define decider. No behavior change (644 corpus / 442 unit).
- vscode grammar: highlight `extern`/`export` as `storage.modifier.sx`.
- vscode packaging: declare `@vscode/vsce` as a devDep + add `package` /
  `vscode:prepublish` scripts so the vsix rebuilds reproducibly (was an
  ambient tool). Add repository/homepage/bugs (Gitea), icon (swipelab logo,
  256x256), galleryBanner, README with cover banner. Rebuilt the vsix.

current/CHECKPOINT-EXTERN-EXPORT.md

@@ -355,11 +355,13 @@ AOT), 1227 (export fn rename, AOT), 1348 (objc extern class), 1349 (objc export
 `#foreign`; the keyword is rejected; zero `foreign` remains in the gated tree (Parts
 A + B, Phases 0–9 all done; the 9.4 gate passes). This stream can be archived.
 
-Possible follow-ups (NOT required, NOT this stream):
-- Optionally add `extern`/`export` to the editors/vscode tmLanguage keyword list (the
-  `#foreign` directive was removed; the new keywords aren't specially highlighted yet).
-- The `RuntimeClassPrefix.is_extern` field + `parseRuntimeClassDecl`'s `is_extern`
-  param are now vestigial (always false post-token-deletion) — a cosmetic cleanup.
+Follow-ups (both DONE 2026-06-15, post-stream polish):
+- ✅ Added `extern`/`export` to the editors/vscode tmLanguage keyword list as a
+  `storage.modifier.sx` pattern (`editors/vscode/syntaxes/sx.tmLanguage.json`).
+- ✅ Dropped the vestigial `RuntimeClassPrefix.is_extern` field +
+  `parseRuntimeClassDecl`'s `is_extern` param (always-false dead path; the postfix
+  `extern`/`export` keyword is the sole reference-vs-define decider). Suite green
+  (644 corpus / 442 unit, 0 failed).
 
 --- (historical: the finish-Phase-9 plan, now done) ---
 **PART B — finish Phase 9: example FILENAME renames + `issues/*.md` + 9.0/9.4.**

editors/vscode/README.md

@@ -0,0 +1,25 @@
+![sx](cover.png)
+
+# sx for Visual Studio Code
+
+Language support for the [sx programming language](https://git.swipelab.com/lab/sx).
+
+## Features
+
+- **Syntax highlighting** for `.sx` files, including embedded GLSL, SQL, HTML, and JSON blocks.
+- **Language server integration** — the extension launches the `sx` binary's language server (`sx lsp`) to provide editor intelligence.
+- **Breakpoints** registered for the `sx` language.
+
+## Requirements
+
+The `sx` compiler must be installed and on your `PATH` (or point the extension at it via the setting below). The extension shells out to it for the language server.
+
+## Settings
+
+| Setting | Default | Description |
+|---------|---------|-------------|
+| `sx.lspPath` | `sx` | Path to the `sx` binary used to start the language server (`sx lsp`). |
+
+## License
+
+See the repository for license details.

editors/vscode/package.json

@@ -4,6 +4,19 @@
   "description": "Language support for the sx programming language",
   "version": "0.0.1",
   "publisher": "swipelab",
+  "icon": "icon.png",
+  "galleryBanner": {
+    "color": "#000000",
+    "theme": "dark"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://git.swipelab.com/lab/sx.git"
+  },
+  "homepage": "https://git.swipelab.com/lab/sx",
+  "bugs": {
+    "url": "https://git.swipelab.com/lab/sx/issues"
+  },
   "engines": {
     "vscode": "^1.75.0"
   },
@@ -73,13 +86,16 @@
   },
   "scripts": {
     "build": "tsc -p .",
-    "watch": "tsc -watch -p ."
+    "watch": "tsc -watch -p .",
+    "vscode:prepublish": "npm run build",
+    "package": "vsce package --baseContentUrl https://git.swipelab.com/lab/sx/src/branch/master/editors/vscode --baseImagesUrl https://git.swipelab.com/lab/sx/raw/branch/master/editors/vscode"
   },
   "dependencies": {
     "vscode-languageclient": "^9.0.1"
   },
   "devDependencies": {
     "@types/vscode": "^1.75.0",
+    "@vscode/vsce": "^3.9.2",
     "typescript": "^5.0.0"
   }
 }

editors/vscode/syntaxes/sx.tmLanguage.json

@@ -193,6 +193,10 @@
           "name": "keyword.other.sx",
           "match": "\\b(enum|struct)\\b"
         },
+        {
+          "name": "storage.modifier.sx",
+          "match": "\\b(extern|export)\\b"
+        },
         {
           "name": "keyword.operator.cast.sx",
           "match": "\\bxx\\b"

src/parser.zig

@@ -258,7 +258,7 @@ pub const Parser = struct {
         // Postfix `extern` flips that to "reference an existing class on the runtime
         // side". `#jni_main` flags the class as the launchable entry (Android Activity).
         if (self.tryParseRuntimeClassPrefix()) |prefix| {
-            return self.parseRuntimeClassDecl(name, start_pos, prefix.runtime, prefix.is_extern, prefix.is_main, name_is_raw);
+            return self.parseRuntimeClassDecl(name, start_pos, prefix.runtime, prefix.is_main, name_is_raw);
         }
 
         // C-style union declaration
@@ -1273,7 +1273,6 @@ pub const Parser = struct {
 
     const RuntimeClassPrefix = struct {
         runtime: ast.RuntimeKind,
-        is_extern: bool,
         is_main: bool,
     };
 
@@ -1285,11 +1284,9 @@ pub const Parser = struct {
     /// state untouched.
     fn tryParseRuntimeClassPrefix(self: *Parser) ?RuntimeClassPrefix {
         // Peek ahead through the optional `#jni_main` modifier to confirm a
-        // runtime-class directive follows. (`is_extern` — reference vs define —
-        // is decided by the POSTFIX `extern`/`export` keyword in parseRuntimeClassDecl,
-        // never a prefix; it stays false here.)
+        // runtime-class directive follows. (reference vs define is decided by the
+        // POSTFIX `extern`/`export` keyword in parseRuntimeClassDecl, never a prefix.)
         var lookahead_idx: usize = 0;
-        const is_extern = false;
         var is_main = false;
         while (true) {
             const tag = self.peekTag(lookahead_idx);
@@ -1305,7 +1302,7 @@ pub const Parser = struct {
         // Commit: consume modifier tokens.
         var i: usize = 0;
         while (i < lookahead_idx) : (i += 1) self.advance();
-        return .{ .runtime = runtime, .is_extern = is_extern, .is_main = is_main };
+        return .{ .runtime = runtime, .is_main = is_main };
     }
 
     fn peekTag(self: *Parser, offset: usize) Tag {
@@ -1340,7 +1337,7 @@ pub const Parser = struct {
         };
     }
 
-    fn parseRuntimeClassDecl(self: *Parser, name: []const u8, start_pos: u32, runtime: ast.RuntimeKind, is_extern: bool, is_main: bool, name_is_raw: bool) anyerror!*Node {
+    fn parseRuntimeClassDecl(self: *Parser, name: []const u8, start_pos: u32, runtime: ast.RuntimeKind, is_main: bool, name_is_raw: bool) anyerror!*Node {
         self.advance(); // skip directive token
 
         try self.expect(.l_paren);
@@ -1356,10 +1353,8 @@ pub const Parser = struct {
         // directive (mirrors `struct #compiler` postfix placement):
         //   `… extern { … }`  ⇒ reference an existing runtime class.
         //   `… export { … }`  ⇒ define + register a new sx class (the default).
-        // Maps onto `is_extern`, threaded into the runtime_class_decl node. (The
-        // passed `is_extern` is always false here — the removed prefix linkage
-        // form is rejected by the caller before this point.)
-        var is_extern_eff = is_extern;
+        // Maps onto `is_extern`, threaded into the runtime_class_decl node.
+        var is_extern_eff = false;
         if (self.current.tag == .kw_extern or self.current.tag == .kw_export) {
             is_extern_eff = self.current.tag == .kw_extern;
             self.advance();