fix: run dynamic app actors as fetch handlers

[NathanFlurry]

Summary

• make deployed Dynamic Apps default-export Fetch handlers instead of starting application-owned servers
• run actor-enabled HTTP routes and Rivet callbacks through one cached agentOS process
• preserve streaming responses with the platform-owned Hono listener and no application health route
• update generated templates, examples, docs, and agentOS dependencies to 0.2.18

Verification

• pnpm build
• all seven example typechecks
• pnpm check-boundaries
• Dynamic Apps E2E typecheck
• generated runner tests: 5/5
• focused actor SSE streaming regression test

Known issue

• repository-wide pnpm check-types remains red because the in-progress static-site tests import a missing staticFetchSource helper and expect static-only deployment validation that is not implemented yet.

[railway-app]

🚅 Environment dynamic-apps-pr-293 in rivet-frontend has no services deployed.

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🚅 Deployed to the dynamic-apps-pr-293 environment in secure-exec

Service	Status	Web	Updated (UTC)
secure-exec	🕒 Building (View Logs)	Web	Aug 31, 2026 at 8:56 pm