chore: strip monorepo; keep Docker runtime deploy for official dsh@latest

Image installs @deepseek-ai/dsh from npm on start. Fork 0.1.2-alpha.2 source
is obsolete for this deployment path.

.gitignore

@@ -0,0 +1,10 @@
+# OS / editor
+.DS_Store
+
+# Local workspace mount created by compose if missing
+workspace/
+
+# Optional local runtime leftovers
+coverage/
+*.tsbuildinfo
+node_modules/