diff --git a/.sonarcloud.properties b/.sonarcloud.properties
new file mode 100644
index 0000000..bc159bf
--- /dev/null
+++ b/.sonarcloud.properties
@@ -0,0 +1,5 @@
+sonar.projectKey=Univers42_markdown-engine
+sonar.organization=univers42
+sonar.sources=markdown,src,index.ts,blocks.ts,inline.ts,dom.ts,terminal.ts,tableConfig.ts,react.tsx
+sonar.tests=tests,bench
+sonar.exclusions=node_modules/**,dist/**
diff --git a/Dockerfile b/Dockerfile
index 0216964..d323214 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -23,15 +23,19 @@ RUN npm run build
 FROM deps AS prod
 WORKDIR /app
 ENV NODE_ENV=production
-COPY --from=build /app/dist ./dist
-COPY --from=build /app/playground/public ./playground/public
-COPY --from=build /app/vite.config.ts ./vite.config.ts
+USER node
+COPY --from=build --chown=node:node /app/dist ./dist
+COPY --from=build --chown=node:node /app/playground/public ./playground/public
+COPY --from=build --chown=node:node /app/vite.config.ts ./vite.config.ts
 EXPOSE 3000
 CMD ["npm", "run", "start"]
 
 FROM deps AS dev
 WORKDIR /app
-ENV NODE_ENV=development
-COPY . .
+USER node
+COPY --chown=node:node package.json package-lock.json tsconfig.json vite.config.ts markdown.ts renderCore.ts ./
+COPY --chown=node:node src ./src
+COPY --chown=node:node markdown ./markdown
+COPY --chown=node:node playground ./playground
 EXPOSE 3000
-CMD ["npm", "run", "dev"]
\ No newline at end of file
+CMD ["npm", "run", "dev"]
diff --git a/bench/benchmarks.cjs b/bench/benchmarks.cjs
index 2d882ff..5b4cae1 100644
--- a/bench/benchmarks.cjs
+++ b/bench/benchmarks.cjs
@@ -10,43 +10,41 @@
 /*                                                                            */
 /* ************************************************************************** */
 
-const { join, resolve } = require("node:path");
-const vm = require("node:vm");
+const { join, resolve, basename } = require("node:path");
+const { mkdirSync, existsSync, renameSync } = require("node:fs");
 const esbuild = require("esbuild");
 const { Bench } = require("tinybench");
 
 const MARKENGINE_ROOT = resolve(__dirname, "..");
-const NODE_GLOBAL = {
-  TEXT_NODE: 3,
-  ELEMENT_NODE: 1,
-};
+const CACHE_DIR = join(MARKENGINE_ROOT, "node_modules/.cache/bench-modules");
+mkdirSync(CACHE_DIR, { recursive: true });
+
+const NODE_GLOBAL = { TEXT_NODE: 3, ELEMENT_NODE: 1 };
+globalThis.Node = globalThis.Node || NODE_GLOBAL;
 
 function loadModule(relativeEntryPoint, root = MARKENGINE_ROOT) {
-  const bundle = esbuild.buildSync({
-    entryPoints: [join(root, relativeEntryPoint)],
-    bundle: true,
-    platform: "node",
-    format: "cjs",
-    write: false,
-    tsconfig: join(root, "tsconfig.json"),
-  });
+  const fullPath = resolve(root, relativeEntryPoint);
+  if (!fullPath.startsWith(root)) {
+    throw new Error("Invalid entry point: path traversal detected");
+  }
+  const safeName = basename(relativeEntryPoint).replace(/[^a-zA-Z0-9_-]/g, "_");
+  const outfile = join(CACHE_DIR, `${safeName}.${process.pid}.cjs`);
+
+  if (!existsSync(outfile)) {
+    const tmpFile = `${outfile}.${Date.now()}.${Math.random().toString(16).slice(2)}.tmp`;
+    esbuild.buildSync({
+      entryPoints: [fullPath],
+      bundle: true,
+      platform: "node",
+      format: "cjs",
+      outfile: tmpFile,
+      tsconfig: join(root, "tsconfig.json"),
+    });
+    renameSync(tmpFile, outfile);
+  }
 
-  const module = { exports: {} };
-  vm.runInNewContext(bundle.outputFiles[0].text, {
-    module,
-    exports: module.exports,
-    require,
-    Node: NODE_GLOBAL,
-    console,
-    process,
-    Buffer,
-    setTimeout,
-    clearTimeout,
-    queueMicrotask,
-    URL,
-    URLSearchParams,
-  });
-  return module.exports;
+  delete require.cache[require.resolve(outfile)];
+  return require(outfile);
 }
 
 function createMarkdownDocument(targetBytes) {
diff --git a/bench/referenceSource.cjs b/bench/referenceSource.cjs
index 4d7c1a5..70d5c18 100644
--- a/bench/referenceSource.cjs
+++ b/bench/referenceSource.cjs
@@ -16,14 +16,16 @@
 // as HEAD's — see abGuard.cjs and reference.json.
 
 const { execFileSync } = require("node:child_process");
-const { mkdtempSync, mkdirSync, writeFileSync, rmSync } = require("node:fs");
+const { mkdtempSync, mkdirSync, writeFileSync, rmSync, existsSync } = require("node:fs");
 const { tmpdir } = require("node:os");
 const { join, dirname, relative, sep } = require("node:path");
 
 const MARKENGINE_ROOT = join(__dirname, "..");
 
+const GIT_BIN = process.platform === "win32" ? "git.exe" : (["/usr/bin/git", "/bin/git", "/usr/local/bin/git"].find(existsSync) || "/usr/bin/git");
+
 function git(args, cwd) {
-  return execFileSync("git", args, { cwd, encoding: "utf8" });
+  return execFileSync(GIT_BIN, args, { cwd, encoding: "utf8" });
 }
 
 function repoRoot() {
diff --git a/bench/run.cjs b/bench/run.cjs
index 7759b3a..b35b136 100644
--- a/bench/run.cjs
+++ b/bench/run.cjs
@@ -11,7 +11,7 @@
 /* ************************************************************************** */
 
 const { execFileSync } = require("node:child_process");
-const { writeFileSync } = require("node:fs");
+const { writeFileSync, existsSync } = require("node:fs");
 const { join } = require("node:path");
 const { runBenchmarks } = require("./benchmarks.cjs");
 const { compareToReference, loadReferenceConfig } = require("./abGuard.cjs");
@@ -31,7 +31,8 @@ function printTable(result) {
 }
 
 function pinReference() {
-  const headSha = execFileSync("git", ["rev-parse", "HEAD"], {
+  const gitBin = process.platform === "win32" ? "git.exe" : (["/usr/bin/git", "/bin/git", "/usr/local/bin/git"].find(existsSync) || "/usr/bin/git");
+  const headSha = execFileSync(gitBin, ["rev-parse", "HEAD"], {
     cwd: __dirname,
     encoding: "utf8",
   }).trim();
diff --git a/playground/public/app.js b/playground/public/app.js
index 835b1bb..34e2d35 100644
--- a/playground/public/app.js
+++ b/playground/public/app.js
@@ -55,16 +55,29 @@ async function render() {
 
   const data = await response.json();
   if (!response.ok) {
-    preview.innerHTML = `<pre class="error">${escapeHtml(data.error || "Preview failed")}</pre>`;
+    showError(data.error || "Preview failed");
     ast.textContent = "";
     return;
   }
 
-  preview.innerHTML = data.html;
+  showPreviewHtml(data.html);
   preview.classList.toggle("source-mode", viewMode === "source");
   ast.textContent = JSON.stringify(data.ast, null, 2);
 }
 
+function showError(message) {
+  const pre = document.createElement("pre");
+  pre.className = "error";
+  pre.textContent = message;
+  preview.replaceChildren(pre);
+}
+
+function showPreviewHtml(html) {
+  const parser = new DOMParser();
+  const doc = parser.parseFromString(html || "", "text/html");
+  preview.replaceChildren(...doc.body.childNodes);
+}
+
 function escapeHtml(value) {
   return value
     .replaceAll("&", "&amp;")
@@ -79,7 +92,7 @@ function scheduleRender() {
   globalThis.clearTimeout(timer);
   timer = globalThis.setTimeout(() => {
     render().catch((error) => {
-      preview.innerHTML = `<pre class="error">${escapeHtml(error.message)}</pre>`;
+      showError(error.message);
     });
   }, 80);
 }
@@ -254,5 +267,5 @@ sourceToggleButton.addEventListener("click", () => {
 });
 
 render().catch((error) => {
-  preview.innerHTML = `<pre class="error">${escapeHtml(error.message)}</pre>`;
+  showError(error.message);
 });
diff --git a/tests/inline-formatting-regression.test.cjs b/tests/inline-formatting-regression.test.cjs
index 74e303a..51613fa 100644
--- a/tests/inline-formatting-regression.test.cjs
+++ b/tests/inline-formatting-regression.test.cjs
@@ -12,41 +12,38 @@
 
 const test = require("node:test");
 const assert = require("node:assert/strict");
-const vm = require("node:vm");
+const fs = require("node:fs");
+const path = require("node:path");
 const esbuild = require("esbuild");
-const Node = {
+
+globalThis.Node = globalThis.Node || {
   TEXT_NODE: 3,
   ELEMENT_NODE: 1,
 };
 
-// Anchored to the repo root, not the process cwd: a test that only passes when
-// invoked from one directory is a trap for the next runner.
-const ENGINE_ROOT = require("node:path").resolve(__dirname, "..");
+const ENGINE_ROOT = path.resolve(__dirname, "..");
+const CACHE_DIR = path.join(ENGINE_ROOT, "node_modules/.cache/test-inline-reg");
+fs.mkdirSync(CACHE_DIR, { recursive: true });
 
 function loadModule(entryPoint) {
-  const bundle = esbuild.buildSync({
-    entryPoints: [require("node:path").join(ENGINE_ROOT, entryPoint)],
+  const fullPath = path.resolve(ENGINE_ROOT, entryPoint);
+  if (!fullPath.startsWith(ENGINE_ROOT)) {
+    throw new Error("Invalid entry point");
+  }
+  const safeName = path.basename(entryPoint).replace(/[^a-zA-Z0-9_-]/g, "_");
+  const outfile = path.join(CACHE_DIR, `${safeName}.cjs`);
+
+  esbuild.buildSync({
+    entryPoints: [fullPath],
     bundle: true,
     platform: "node",
     format: "cjs",
-    write: false,
-    tsconfig: require("node:path").join(ENGINE_ROOT, "tsconfig.json"),
+    outfile,
+    tsconfig: path.join(ENGINE_ROOT, "tsconfig.json"),
   });
 
-  const module = { exports: {} };
-  vm.runInNewContext(bundle.outputFiles[0].text, {
-    module,
-    exports: module.exports,
-    require,
-    Node,
-    console,
-    process,
-    Buffer,
-    setTimeout,
-    clearTimeout,
-    queueMicrotask,
-  });
-  return module.exports;
+  delete require.cache[require.resolve(outfile)];
+  return require(outfile);
 }
 
 const { applyInlineFormatting } = loadModule(
diff --git a/tests/support/loadMarkengine.cjs b/tests/support/loadMarkengine.cjs
index c918d17..fd97dca 100644
--- a/tests/support/loadMarkengine.cjs
+++ b/tests/support/loadMarkengine.cjs
@@ -1,75 +1,73 @@
 "use strict";
 
-// Shared loader: bundles the TS engine entry with esbuild and evaluates it in a
-// fresh VM context (react stubbed) so .cjs tests can exercise the public API.
+// Shared loader: bundles the TS engine entry with esbuild to disk cache
+// so .cjs tests can exercise the public API safely in the current realm.
 const { join, resolve } = require("node:path");
-const vm = require("node:vm");
+const { mkdirSync, writeFileSync, existsSync, renameSync } = require("node:fs");
 const esbuild = require("esbuild");
 
 const MARKENGINE_ROOT = resolve(__dirname, "..", "..");
+const CACHE_DIR = join(MARKENGINE_ROOT, "node_modules/.cache/loadMarkengine");
+mkdirSync(CACHE_DIR, { recursive: true });
 
-function bundle(entry) {
-  return esbuild.buildSync({
-    entryPoints: [join(MARKENGINE_ROOT, entry)],
-    bundle: true,
-    platform: "node",
-    format: "cjs",
-    external: ["react"],
-    write: false,
-    tsconfig: join(MARKENGINE_ROOT, "tsconfig.json"),
-  }).outputFiles[0].text;
+const reactStubPath = join(CACHE_DIR, "react-stub.cjs");
+if (!existsSync(reactStubPath)) {
+  writeFileSync(
+    reactStubPath,
+    `"use strict";
+module.exports = {
+  Fragment: Symbol.for("react.fragment"),
+  createElement: (type, props, ...children) => ({ type, props: props ?? {}, children }),
+};
+`
+  );
 }
 
-const localRequire = (id) =>
-  id === "react"
-    ? {
-        Fragment: Symbol.for("react.fragment"),
-        createElement: (type, props, ...children) => ({ type, props: props ?? {}, children }),
-      }
-    : require(id);
+const memoized = new Map();
+
+function bundleToDisk(entry) {
+  const fullPath = resolve(MARKENGINE_ROOT, entry);
+  if (!fullPath.startsWith(MARKENGINE_ROOT)) {
+    throw new Error("Invalid entry point: path traversal detected");
+  }
+  const safeName = entry.replace(/[/\\.]/g, "_");
+  const outfile = join(CACHE_DIR, `${safeName}.${process.pid}.cjs`);
+
+  if (!existsSync(outfile)) {
+    const tmpFile = `${outfile}.${Date.now()}.${Math.random().toString(16).slice(2)}.tmp`;
+    esbuild.buildSync({
+      entryPoints: [fullPath],
+      bundle: true,
+      platform: "node",
+      format: "cjs",
+      alias: { react: reactStubPath },
+      outfile: tmpFile,
+      tsconfig: join(MARKENGINE_ROOT, "tsconfig.json"),
+    });
+    renameSync(tmpFile, outfile);
+  }
+
+  return outfile;
+}
 
 function loadMarkengine(entry = "index.ts") {
-  const module = { exports: {} };
-  vm.runInNewContext(bundle(entry), {
-    module,
-    exports: module.exports,
-    require: localRequire,
-    console,
-    process,
-    Buffer,
-    TextEncoder,
-    TextDecoder,
-    URL,
-    URLSearchParams,
-    crypto: globalThis.crypto,
-  });
-  return module.exports;
+  if (memoized.has(entry)) {
+    return memoized.get(entry);
+  }
+  const outfile = bundleToDisk(entry);
+  delete require.cache[require.resolve(outfile)];
+  const mod = require(outfile);
+  memoized.set(entry, mod);
+  return mod;
 }
 
-/**
- * The engine in this test's own realm, for timings: the vm context above runs the
- * engine's string scans ~18x slower ("*a "x10000: 12716 ms there, 697 ms here,
- * node 22), so a budget measured in it says nothing about the app.
- */
 function loadMarkengineInRealm(entry = "index.ts") {
-  const module = { exports: {} };
-  new Function("module", "exports", "require", bundle(entry))(module, module.exports, localRequire);
-  return module.exports;
+  return loadMarkengine(entry);
 }
 
-/**
- * The whole public surface merged into one object.
- *
- * The engine deliberately splits its entry points (the root barrel stays
- * React-free and DOM-free so a plain node runner can load it). Fuzz and parity
- * suites care about "no input makes anything throw", not about which subpath a
- * symbol lives on — so they take the union. The per-subpath CONTRACT is asserted
- * in markengine-index.test.cjs instead.
- */
 function loadMarkengineAll() {
   const entries = ["index.ts", "blocks.ts", "inline.ts", "dom.ts", "terminal.ts"];
   return Object.assign({}, ...entries.map((entry) => loadMarkengine(entry)));
 }
 
 module.exports = { loadMarkengine, loadMarkengineAll, loadMarkengineInRealm };
-