feat(FN-3239): auto-install dependency graph plugin in CLI daemon, dashboar

Merged the three-step FN-3239 feature: auto-installing the dependency graph plugin on first run across the `daemon`, `dashboard`, and `serve` commands, with the core logic centralized in `bundled-plugin-install.ts`, bundling configuration in `tsup.config.ts`, and a documentation file for the default

Fusion-Task-Id: FN-3239

packages/cli/src/plugins/bundled-plugin-install.ts

@@ -0,0 +1,67 @@
+import { existsSync } from "node:fs";
+import { readFile } from "node:fs/promises";
+import { dirname, join, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+import { validatePluginManifest, type PluginLoader, type PluginManifest, type PluginStore } from "@fusion/core";
+
+const DEPENDENCY_GRAPH_PLUGIN_ID = "fusion-plugin-dependency-graph";
+
+function getCandidatePluginPaths(): string[] {
+  const moduleDir = dirname(fileURLToPath(import.meta.url));
+  const cliPackageRoot = resolve(moduleDir, "..", "..");
+
+  return [
+    join(cliPackageRoot, "dist", "plugins", DEPENDENCY_GRAPH_PLUGIN_ID),
+    join(cliPackageRoot, "plugins", DEPENDENCY_GRAPH_PLUGIN_ID),
+    join(cliPackageRoot, "..", "..", "plugins", DEPENDENCY_GRAPH_PLUGIN_ID),
+  ];
+}
+
+async function loadManifest(pluginDir: string): Promise<PluginManifest> {
+  const manifestPath = join(pluginDir, "manifest.json");
+  const content = await readFile(manifestPath, "utf-8");
+  const manifest = JSON.parse(content);
+  const validation = validatePluginManifest(manifest);
+  if (!validation.valid) {
+    throw new Error(`Invalid plugin manifest: ${validation.errors.join(", ")}`);
+  }
+  return manifest;
+}
+
+function resolveBundledDependencyGraphPath(): string | null {
+  for (const path of getCandidatePluginPaths()) {
+    if (existsSync(join(path, "manifest.json"))) {
+      return path;
+    }
+  }
+  return null;
+}
+
+export async function ensureBundledDependencyGraphPluginInstalled(
+  pluginStore: PluginStore,
+  pluginLoader: PluginLoader,
+): Promise<"installed" | "already-installed" | "missing-bundle"> {
+  try {
+    await pluginStore.getPlugin(DEPENDENCY_GRAPH_PLUGIN_ID);
+    return "already-installed";
+  } catch {
+    // Continue; plugin not installed yet.
+  }
+
+  const bundledPath = resolveBundledDependencyGraphPath();
+  if (!bundledPath) {
+    return "missing-bundle";
+  }
+
+  const manifest = await loadManifest(bundledPath);
+  const plugin = await pluginStore.registerPlugin({
+    manifest,
+    path: bundledPath,
+  });
+
+  if (plugin.enabled) {
+    await pluginLoader.loadPlugin(plugin.id);
+  }
+
+  return "installed";
+}