Move docs/ package mirror into document-navigator plugin

Relocate the ~6k-file docs tree from the repo root into
plugins/document-navigator/docs/ so the plugin is self-contained and
portable. docs/superpowers/ (specs and plans) stays at the repo root.

Moved via cp+rm rather than git mv because directory rename() fails with
EPERM on this WSL /mnt DrvFs mount; git rename-detection pairs the
identical-content files at commit time.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

plugins/document-navigator/docs/testkit/testing/testing-dom/src/render/render-component.md

@@ -0,0 +1,60 @@
+# render-component
+
+<!-- begin:auto-docs -->
+_(no submodules)_
+<!-- end:auto-docs -->
+## Purpose
+
+`renderComponent` wraps `@testing-library/react`'s `render` with two project-wide defaults: (1) it calls `cleanup()` before mounting so orphaned trees from a previous test never pollute the current test's query space, and (2) it throws `TestingDomError("TESTING_DOM.RENDER.FAILED")` on any underlying failure so callers always see a typed error with structured context.
+
+## Features
+
+- Automatic pre-mount `cleanup()` — no stray DOM from prior tests
+- Typed failure mode via `TestingDomError`
+- Thin wrapper — returns the same `RenderResult` as upstream
+- Accepts the full `RenderOptions` surface (`container`, `baseElement`, `hydrate`, `wrapper`)
+
+## Usage: Basic Example
+
+```tsx
+import { renderComponent } from "@suaveplan/testing-dom";
+
+const { getByRole } = renderComponent(<button>save</button>);
+expect(getByRole("button", { name: "save" })).toBeInTheDocument();
+```
+
+## Usage: Advanced Example
+
+```tsx
+import { renderComponent, TestingDomError, TESTING_DOM_CODES } from "@suaveplan/testing-dom";
+import { MyProvider } from "./MyProvider";
+
+const Wrapper: React.FC<{ children: React.ReactNode }> = ({ children }) => (
+    <MyProvider>{children}</MyProvider>
+);
+
+try {
+    const { container, rerender } = renderComponent(<App />, { wrapper: Wrapper });
+    expect(container.firstChild).toHaveTextContent("Hello");
+    rerender(<App locale="fr" />);
+    expect(container.firstChild).toHaveTextContent("Bonjour");
+} catch (err) {
+    if (err instanceof TestingDomError && err.code === TESTING_DOM_CODES.RENDER_FAILED) {
+        console.error("render failed:", err.cause);
+    }
+    throw err;
+}
+```
+
+## API Reference
+
+### `renderComponent(ui, options?): RenderResult`
+
+- `ui` — React element or functional component
+- `options` — passed through to upstream `render` (full `RenderOptions` surface)
+- Returns the upstream `RenderResult` unchanged
+- Throws `TestingDomError("TESTING_DOM.RENDER.FAILED")` on any underlying failure, preserving `cause`
+
+## Implementation Notes
+
+Calling `cleanup()` BEFORE mount (rather than after) is deliberate — it means a test file that forgot to register `afterEach(cleanup)` still gets isolated trees between tests. It also avoids the subtle afterEach-ordering issue where a cleanup hook might fire before the test's expectations if another `afterEach` throws. Catching and rethrowing as `TestingDomError` normalises the error surface for downstream code; the underlying testing-library error lives on `err.cause` for debugging.