Use match for value dispatch in evaluator and compiler

Convert large cond chains doing string equality dispatch to use the
match special form: step-eval-list (42 arms), step-continue (31 arms),
compile-list (30 arms), ho-setup-dispatch (7 arms), value-matches-type?
(10 arms). Also fix test-canonical.sx to use defsuite/deftest format
and load canonical.sx in both test runners.

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

hosts/javascript/run_tests.js

@@ -82,6 +82,18 @@ env["env-merge"] = function(a, b) { return Object.assign({}, a, b); };
 
 // Missing primitives referenced by tests
 // primitive? is now in platform.py PRIMITIVES
+env["contains-char?"] = function(s, c) { return typeof s === "string" && typeof c === "string" && s.indexOf(c) >= 0; };
+env["escape-string"] = function(s) { return s.replace(/\\/g, "\\\\").replace(/"/g, '\\"').replace(/\n/g, "\\n").replace(/\t/g, "\\t"); };
+env["trim-right"] = function(s) { return typeof s === "string" ? s.trimEnd() : s; };
+env["sha3-256"] = function(s) {
+  // Simple hash stub for testing — not real SHA3
+  var h = 0;
+  for (var i = 0; i < s.length; i++) { h = ((h << 5) - h + s.charCodeAt(i)) | 0; }
+  h = Math.abs(h);
+  var hex = h.toString(16);
+  while (hex.length < 64) hex = "0" + hex;
+  return hex;
+};
 env["upcase"] = function(s) { return s.toUpperCase(); };
 env["downcase"] = function(s) { return s.toLowerCase(); };
 env["make-keyword"] = function(name) { return new Sx.Keyword(name); };
@@ -291,6 +303,18 @@ if (fs.existsSync(harnessPath)) {
   }
 }
 
+// Load canonical.sx (content-addressing, serialization)
+const canonicalPath = path.join(projectDir, "spec", "canonical.sx");
+if (fs.existsSync(canonicalPath)) {
+  const canonicalSrc = fs.readFileSync(canonicalPath, "utf8");
+  const canonicalExprs = Sx.parse(canonicalSrc);
+  for (const expr of canonicalExprs) {
+    try { Sx.eval(expr, env); } catch (e) {
+      console.error(`Error loading canonical.sx: ${e.message}`);
+    }
+  }
+}
+
 // Load compiler + VM from lib/ when running full tests
 if (fullBuild) {
   const libDir = path.join(projectDir, "lib");