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.

AGENTS.md

@@ -24,6 +24,7 @@ packages/    @deepseek-ai/dsh-<pkg> workspaces at packages/<group>/<pkg>/
   compact/     compaction seam + basic backend
   context/     request-context plugins
   subagent/    subagent seam + spawn/fork/ACP backends + delegation tool
+  bundle/      profile plugin bundles: installable patch layers for dsh --profile
   workflow/    workflow seam + worker-thread engine + workflow tool
   todo/        todo_write tool
   plan/        plan mode as logged per-agent collaboration state