Resumed sessions showed raw JSON tool output in content boxes instead
of the compact trail lines seen during live use. The root cause was
two separate rendering paths with no shared code.
Extract buildToolTrailLine() into lib/text.ts as the single source
of truth for formatting tool trail lines. Both the live tool.complete
handler and toTranscriptMessages now call it.
Server-side, reconstruct tool name and args from the assistant
message's tool_calls field (tool_name column is unpopulated) and
pass them through _tool_ctx/build_tool_preview — the same path
the live tool.start callback uses.
Brooklyn Nicholson