feat(web): add read-only Loader plugin inventory

packages/host/plugin-inventory/tests/invariant.spec.ts

@@ -0,0 +1,16 @@
+import { Context } from '@deepseek-ai/cordis'
+import { describe, expect, it } from 'vitest'
+import InvariantService from '@deepseek-ai/dsh-invariants'
+import * as PluginInventoryInvariant from '../src/invariant.ts'
+
+describe('plugin-inventory invariant companion', () => {
+  it('registers the package-owned empty installer', async () => {
+    const ctx = new Context()
+    await ctx.plugin(InvariantService, { enabled: true })
+    const fiber = ctx.plugin(PluginInventoryInvariant)
+    await expect(fiber.await()).resolves.toBeDefined()
+    await fiber.dispose()
+    await expect(ctx.plugin(PluginInventoryInvariant).await()).resolves.toBeDefined()
+    await ctx.fiber.dispose()
+  })
+})