[fix] Include routed member responses in team history

[Fahmid-Arman]

Summary

Fixes #8573.

This PR fixes route-mode team history and session summary context dropping routed member assistant responses.

In route/respond-directly teams, the delegated member response is returned as the team response, but the stored team-level run may not include that assistant message. The actual assistant answer is stored on the member run. Existing history and summary builders used the default member-message filtering behavior, so routed assistant responses were omitted from replayed history and session summaries.

Changes:

• Include routed member responses when building history for respond-directly teams
• Include routed member responses in route-mode session summary context
• Preserve coordinate-mode behavior
• Add regression coverage for sync and async route-mode history replay

Type of change

• Bug fix
• New feature
• Breaking change
• Improvement
• Model update
• Other:

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Checklist

• Code complies with style guidelines
• Ran format/validation scripts (./scripts/format.sh and ./scripts/validate.sh)
• Self-review completed
• Documentation updated (comments, docstrings)
• Examples and guides: Relevant cookbook examples have been included or updated (if applicable)
• Tested in clean environment
• Tests added/updated (if applicable)

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Tests

./scripts/format.sh
pytest -q libs/agno/tests/unit/team/test_get_messages_dedup.py libs/agno/tests/unit/team/test_route_mode_history.py
./scripts/validate.sh