VM spec in SX + 72 tests passing on both JS and OCaml

spec/vm.sx — bytecode VM written in SX (the spec):
  - Stack-based interpreter for bytecode from compiler.sx
  - 24 opcodes: constants, variables (local/upvalue/global), control flow,
    function calls (with TCO), closures with upvalue capture, collections,
    string concat, define
  - Upvalue cells for shared mutable closure variables
  - Call dispatch: vm-closure (fast path), native-fn, CEK fallback
  - Platform interface: 7 primitives (vm-stack-*, call-primitive, cek-call,
    get-primitive, env-parent)

spec/tests/test-vm.sx — 72 tests exercising compile→bytecode→VM pipeline:
  constants, arithmetic, comparison, control flow (if/when/cond/case/and/or),
  let bindings, lambda, closures, upvalue mutation, TCO (10K iterations),
  collections, strings, define, letrec, quasiquote, threading, integration
  (fibonacci, recursive map/filter/reduce, compose)

spec/compiler.sx — fix :else keyword detection in case/cond compilation
  (was comparing Keyword object to evaluated string, now checks type)

Platform primitives added (JS + OCaml):
  make-vm-stack, vm-stack-get, vm-stack-set!, vm-stack-length, vm-stack-copy!,
  primitive?, get-primitive, call-primitive, set-nth! (JS)

Test runners updated to load bytecode.sx + compiler.sx + vm.sx for --full.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/javascript/run_tests.js

@@ -81,6 +81,7 @@ env["env-extend"] = function(e) { return Object.create(e); };
 env["env-merge"] = function(a, b) { return Object.assign({}, a, b); };
 
 // Missing primitives referenced by tests
+// primitive? is now in platform.py PRIMITIVES
 env["upcase"] = function(s) { return s.toUpperCase(); };
 env["downcase"] = function(s) { return s.toLowerCase(); };
 env["make-keyword"] = function(name) { return new Sx.Keyword(name); };
@@ -277,6 +278,23 @@ for (const expr of frameworkExprs) {
   Sx.eval(expr, env);
 }
 
+// Load compiler + VM spec when running full tests
+if (fullBuild) {
+  const specDir = path.join(projectDir, "spec");
+  for (const specFile of ["bytecode.sx", "compiler.sx", "vm.sx"]) {
+    const specPath = path.join(specDir, specFile);
+    if (fs.existsSync(specPath)) {
+      const src = fs.readFileSync(specPath, "utf8");
+      const exprs = Sx.parse(src);
+      for (const expr of exprs) {
+        try { Sx.eval(expr, env); } catch (e) {
+          console.error(`Error loading ${specFile}: ${e.message}`);
+        }
+      }
+    }
+  }
+}
+
 // Determine which tests to run
 const args = process.argv.slice(2).filter(a => !a.startsWith("--"));
 let testFiles = [];
@@ -293,7 +311,7 @@ if (args.length > 0) {
   }
 } else {
   // Tests requiring optional modules (only run with --full)
-  const requiresFull = new Set(["test-continuations.sx", "test-types.sx", "test-freeze.sx"]);
+  const requiresFull = new Set(["test-continuations.sx", "test-continuations-advanced.sx", "test-types.sx", "test-freeze.sx", "test-vm.sx"]);
   // All spec tests
   for (const f of fs.readdirSync(specTests).sort()) {
     if (f.startsWith("test-") && f.endsWith(".sx") && f !== "test-framework.sx") {