Make test.sx self-executing: evaluators run it directly, no codegen

test.sx now defines deftest/defsuite as macros. Any host that provides
5 platform functions (try-call, report-pass, report-fail, push-suite,
pop-suite) can evaluate the file directly — no bootstrap compilation
step needed for JS.

- Added defmacro for deftest (wraps body in thunk, catches via try-call)
- Added defmacro for defsuite (push/pop suite context stack)
- Created run.js: sx-browser.js evaluates test.sx directly (81/81 pass)
- Created run.py: Python evaluator evaluates test.sx directly (81/81 pass)
- Deleted bootstrap_test_js.py and generated test_sx_spec.js
- Updated testing docs page to reflect self-executing architecture

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

shared/sx/tests/run.js

@@ -0,0 +1,108 @@
+// Run test.sx directly against sx-browser.js.
+//
+// sx-browser.js parses and evaluates test.sx — SX tests itself.
+// This script provides only platform functions (error catching, reporting).
+//
+// Usage: node shared/sx/tests/run.js
+
+Object.defineProperty(globalThis, "document", { value: undefined, writable: true });
+var path = require("path");
+var fs = require("fs");
+var Sx = require(path.resolve(__dirname, "../../static/scripts/sx-browser.js"));
+
+// --- Test state ---
+var suiteStack = [];
+var passed = 0, failed = 0, testNum = 0;
+
+// --- Helpers ---
+function isNil(x) { return x === Sx.NIL || x === null || x === undefined; }
+
+function deepEqual(a, b) {
+  if (a === b) return true;
+  if (isNil(a) && isNil(b)) return true;
+  if (typeof a !== typeof b) return false;
+  if (Array.isArray(a) && Array.isArray(b)) {
+    if (a.length !== b.length) return false;
+    for (var i = 0; i < a.length; i++) if (!deepEqual(a[i], b[i])) return false;
+    return true;
+  }
+  if (a && typeof a === "object" && b && typeof b === "object") {
+    var ka = Object.keys(a), kb = Object.keys(b);
+    if (ka.length !== kb.length) return false;
+    for (var j = 0; j < ka.length; j++) if (!deepEqual(a[ka[j]], b[ka[j]])) return false;
+    return true;
+  }
+  return false;
+}
+
+// --- Platform functions injected into the SX env ---
+var env = {
+  // Error catching — calls an SX thunk, returns result dict
+  "try-call": function(thunk) {
+    try {
+      Sx.eval([thunk], env);
+      return { ok: true };
+    } catch(e) {
+      return { ok: false, error: e.message || String(e) };
+    }
+  },
+
+  // Test reporting
+  "report-pass": function(name) {
+    testNum++;
+    passed++;
+    var fullName = suiteStack.concat([name]).join(" > ");
+    console.log("ok " + testNum + " - " + fullName);
+  },
+  "report-fail": function(name, error) {
+    testNum++;
+    failed++;
+    var fullName = suiteStack.concat([name]).join(" > ");
+    console.log("not ok " + testNum + " - " + fullName);
+    console.log("  # " + error);
+  },
+
+  // Suite context
+  "push-suite": function(name) { suiteStack.push(name); },
+  "pop-suite": function() { suiteStack.pop(); },
+
+  // Primitives that sx-browser.js has internally but doesn't expose through env
+  "equal?": function(a, b) { return deepEqual(a, b); },
+  "eq?": function(a, b) { return a === b; },
+  "boolean?": function(x) { return typeof x === "boolean"; },
+  "string-length": function(s) { return String(s).length; },
+  "substring": function(s, start, end) { return String(s).slice(start, end); },
+  "string-contains?": function(s, needle) { return String(s).indexOf(needle) !== -1; },
+  "upcase": function(s) { return String(s).toUpperCase(); },
+  "downcase": function(s) { return String(s).toLowerCase(); },
+  "reverse": function(c) { return c ? c.slice().reverse() : []; },
+  "flatten": function(c) {
+    var r = [];
+    for (var i = 0; i < (c||[]).length; i++) {
+      if (Array.isArray(c[i])) for (var j = 0; j < c[i].length; j++) r.push(c[i][j]);
+      else r.push(c[i]);
+    }
+    return r;
+  },
+  "has-key?": function(d, k) { return d && typeof d === "object" && k in d; },
+  "append": function(c, x) { return Array.isArray(x) ? (c||[]).concat(x) : (c||[]).concat([x]); },
+};
+
+// --- Read and evaluate test.sx ---
+var src = fs.readFileSync(path.resolve(__dirname, "../ref/test.sx"), "utf8");
+var exprs = Sx.parseAll(src);
+
+console.log("TAP version 13");
+for (var i = 0; i < exprs.length; i++) {
+  Sx.eval(exprs[i], env);
+}
+
+// --- Summary ---
+console.log("");
+console.log("1.." + testNum);
+console.log("# tests " + (passed + failed));
+console.log("# pass  " + passed);
+if (failed > 0) {
+  console.log("# fail  " + failed);
+  process.exit(1);
+}