refactor: introduce RevealManager and Article DOM context

Decouple the reveal logic from the `Article` component by introducing
a `RevealManager` component and an `ArticleDomCtx`. This allows the
reveal logic to reactively manage DOM injections and classes without
polluting the `Article` component's props or lifecycle.

Additionally, implements a robust `cleanupInjections` mechanism to
ensure that injected buttons and styling artifacts are properly removed
during navigation, role changes, or disconnections.

src/components/RevealManager.tsx

@@ -0,0 +1,40 @@
+/**
+ * RevealManager — mounts as a child of <Article> and reactively applies
+ * reveal classes (non-GM) or injects action buttons (GM) whenever the
+ * content DOM, stream connection state, role, or completions change.
+ */
+
+import { Component, createEffect, onCleanup } from "solid-js";
+import { useLocation } from "@solidjs/router";
+import { useArticleDom } from "./Article";
+import { journalStreamState } from "./stores/journalStream";
+import { useJournalCompletions } from "./journal/completions";
+import { addRevealedClasses, cleanupInjections } from "./stores/reveal";
+
+export const RevealManager: Component = () => {
+  const contentDom = useArticleDom();
+  const location = useLocation();
+  const comp = useJournalCompletions();
+
+  createEffect(() => {
+    const dom = contentDom();
+    if (!dom) return;
+
+    // Access stream state reactively so the effect re-runs whenever
+    // connection status or role changes.
+    const state = journalStreamState;
+    void state.connected;
+    void state.myRole;
+
+    addRevealedClasses(dom, location.pathname, comp.data);
+  });
+
+  onCleanup(() => {
+    const dom = contentDom();
+    if (dom) cleanupInjections(dom);
+  });
+
+  return null;
+};
+
+export default RevealManager;