Add negotiated error pages and use them

Introduce a self-contained, content-negotiated error page renderer (HTML/JSON/text) in crates/nexide/src/server/error_page.rs and tests. Integrate it into the server by wiring it into next_bridge and static_assets so dispatch failures and handler errors return polished responses (with optional machine-readable detail) instead of plain text. Update module registration in server/mod.rs. Improve runtime polyfill cjs_loader.js to track a moduleStack so dynamic imports without an explicit referrer resolve relative to the calling module, and add a test for that behavior in crates/nexide/tests/cjs_loader.rs. Finally, bump workspace version to 0.1.15 in Cargo.toml and update Cargo.lock accordingly.

Author: sonquer

Cargo.lock

@@ -7,7 +7,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.1.14"
+version = "0.1.15"
 edition = "2024"
 license = "MIT OR Apache-2.0"
 publish = false

Cargo.toml

@@ -14,6 +14,7 @@
 
   const ops = Nexide.core.ops;
   const cache = new Map();
+  const moduleStack = [];
 
   function dirnameOf(spec) {
     if (typeof spec !== "string" || spec.length === 0) return "";
@@ -37,7 +38,15 @@
       source +
       "\n})\n//# sourceURL=" +
       specifier;
-    return (0, eval)(wrapper);
+    const fn = (0, eval)(wrapper);
+    return function (exports, require, module, __filename, __dirname) {
+      moduleStack.push(specifier);
+      try {
+        return fn(exports, require, module, __filename, __dirname);
+      } finally {
+        moduleStack.pop();
+      }
+    };
   }
 
   function makeRequire(parent) {
@@ -117,9 +126,14 @@
   }
 
   function dynamicImport(specifier, referrer) {
-    const parent = (typeof referrer === "string" && referrer.length > 0)
-      ? referrer
-      : ops.op_cjs_root_parent();
+    let parent;
+    if (typeof referrer === "string" && referrer.length > 0) {
+      parent = referrer;
+    } else if (moduleStack.length > 0) {
+      parent = moduleStack[moduleStack.length - 1];
+    } else {
+      parent = ops.op_cjs_root_parent();
+    }
     const exports = loadModule(parent, specifier);
     return buildNamespace(exports);
   }