Add advanced agent orchestration examples

## Goal

Add runnable examples to the example app for the advanced workflow patterns listed in the Agent workflows documentation.

## Acceptance criteria

- Demonstrate dynamic routing to specialist agents.
- Demonstrate parallel LLM fan-out with a combined answer.
- Demonstrate coordinating multiple agents.
- Demonstrate a bounded Reasoning and Acting (ReAct) loop.
- Demonstrate agents exchanging messages as a network.
- Demonstrate a durable workflow that pauses and resumes.
- Expose the examples from the example app with concise explanatory copy.
- Typecheck, lint, and relevant tests pass.

Start with the example app and the Agent workflows documentation to locate the existing examples and navigation or presentation structure. Add runnable demonstrations for each listed orchestration pattern, expose them with concise explanatory copy, then run typechecking, linting, and the relevant tests. Done means all seven patterns are represented and the stated checks pass.

Written by the indexing model from the issue text.