Harness Open A2A Network Plugin

Key features

• Model tools — a2a_teams lists the teams this node can see (own, peers', joined sessions')
• Storage/a2a/canvas.json (ordered team entries
• Roles — one session, one office, no crossing workspace boundaries: a research node (protocol/design review, verdict criteria, source-line references with must-fix/recommend labels), a maintainer node (version rulings, releases, adoption receipts), a test node (the single execution point for all live-host verification
• a2a_route sends one message to a team, reuses context_id to continue a remote conversation, and fails over across candidates when a peer is unreachable.
• a2a_probe measures the tracked fleet's reachability and round-trip latency (one verified-card fetch per peer, optionally narrowed to a single url) for pre-dispatch health checks, naming each miss's stage — unreachable (transport/HTTP) vs.