Summary

• coalesce adjacent assistant message chunks into the current chat bubble
• keep tool/status/error boundaries as separate transcript rows
• add web smoke coverage for headless zarvis-style streamed message deltas

Tests

• cargo build --workspace
• cargo test -p agentd-e2e web_client_loads_and_websocket_connects -- --nocapture
• git diff --check

Note: cargo fmt --check reports existing formatting drift in unrelated Rust files, so I did not run a workspace-wide format rewrite.