fix: update tests and fix running on main-0.6

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Summary

• Switch from webrtc to quic network transport (kitsune2 removed webrtc subcommand)
• Use irohTransport config instead of tx5Transport (kitsune2 uses iroh, not tx5)
• Use http:// scheme for relay URL — iroh requires HTTP to connect to the relay and establish a public endpoint
• Set signal_url to local bootstrap server address
• Increase dhtSync default timeout from 40s to 60s for kitsune2 gossip timing
• Bump version to 0.19.1

Test plan

• Verified single-conductor tests pass (dna-properties)
• Verified multi-conductor gossip/dhtSync works (agent-to-notifications)
• Verified followed-creators-mews tests pass