allowedDirectory containment uses a raw string prefix, so a sibling directory sharing a name prefix passes the check

`security/jsLoader.ts:1202-1211`:

```js
if (moduleUrl.startsWith('file:')) {
let path = fileURLToPath(moduleUrl);
try { path = realpathSync(path); } catch {}
if (!allowedPath || path.startsWith(allowedPath)) { return; }
throw new Error(`Can not load module at ${path} outside of allowed path ${allowedPath}`);
}
```

`allowedPath` is the realpath of the component directory (`components/componentLoader.ts:729`), and containment is a bare `String.prototype.startsWith`. It is not separator-aware, so an application rooted at `/components/foo` can load `/components/foo-other/file.js` — the string test passes even though the file is outside the application's tree.

With `applications.allowedDirectory: app` (the default in production since v5.0.4), that means the directory restriction can be satisfied by any sibling path sharing a name prefix.

Suggested fix — a `path.relative` containment check:

```js
const rel = relative(allowedPath, path);
if (!rel || (!rel.startsWith('..' + sep) && rel !== '..' && !isAbsolute(rel))) return;
```

Worth a test for the sibling-prefix case specifically (`/x/app` vs `/x/app-other`), since that is the one a prefix comparison gets wrong.

Related: #2505 covers a separate gap in the same check — the CommonJS path does not call it at all.

Found while documenting module loading in HarperFast/documentation#664 (review comment from @kriszyp). That PR describes `allowedDirectory` as a configuration guardrail rather than a security boundary; it can be stated more strongly once this and #2505 are fixed.

_{sent with Claude Opus 5}

Start in security/jsLoader.ts:1202-1211 and compare allowedPath construction in components/componentLoader.ts:729. Trace the file-URL loading path, then add a regression test for sibling prefixes such as /x/app versus /x/app-other. Done means paths outside the allowed directory are rejected while paths within it remain allowed.

Written by the indexing model from the issue text.