feat(bundle): ship dsh-base, dsh-web-app, and dsh-headless profile bundles

Profile bundles are npm packages declaring dsh.patch in their manifest:
dsh-base carries the former base.cordis.yml rows as one insert over the empty
profile root; dsh-web-app carries the web overlay plus a runtime glue plugin
owning what used to be launcher code (frontend dist resolution via
frontend-static, the web-surface prompt section, bash runtime variables, the
readiness-gated URL line); dsh-headless carries the one-shot runner driving a
task turn through the in-process API carrier under the launcher-provided
ctx.headlessIo seam.

packages/bundle/web-app/src/invariant.ts

@@ -0,0 +1,30 @@
+/**
+ * Package-owned invariant companion for `@deepseek-ai/dsh-web-app`.
+ * @module @deepseek-ai/dsh-web-app/invariant
+ */
+
+import type { Context } from 'cordis'
+import type { InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+
+const PACKAGE_NAME = '@deepseek-ai/dsh-web-app'
+
+/** Cordis companion plugin name. */
+export const name = 'web-app-invariant'
+/** Service required before the companion can register. */
+export const inject = ['invariants']
+
+/**
+ * No runtime invariant: every contribution (frontend-static child plugin,
+ * prompt section, bashEnv registration) is registry-disposed with the fiber,
+ * and each owning registry's package carries that relation's invariant; the
+ * package holds no mutable state of its own to audit.
+ */
+const install: InvariantInstaller = () => {}
+
+/**
+ * Register this package's invariant companion.
+ * @param ctx - Cordis context carrying the invariant service.
+ * @returns the installed registration's disposer after setup succeeds.
+ */
+export const apply = (ctx: Context): Promise<() => void> =>
+  Promise.resolve(ctx.invariants.register(PACKAGE_NAME, install))