Add a --format-logs flag to skybridge dev for structured log formatting

[pldesch-chift]

Problem

When using structured JSON loggers like bunyan or pino, the raw JSON output appears in the Skybridge dev UI as unreadable single-line records like:

{"name":"chift-mcp","hostname":"...","pid":40327,"level":30,"msg":"request received","time":"2026-05-27T15:23:38.950Z","v":0}

The standard way to make this readable is to pipe through the formatter CLI (| bunyan), but this is not possible with Skybridge because the Ink UI captures stdout internally via nodemon. Piping the whole skybridge dev process swallows the Ink UI (banner, tunnel info, TS errors).

Proposed solution

Add a --format-logs <command> flag to skybridge dev that:

1. Spawns the formatter command as a single long-lived child process
2. Pipes each server stdout line through its stdin
3. Reads formatted output from the formatter via readline
4. Displays the formatted lines in the existing Ink UI

skybridge dev --format-logs bunyan
skybridge dev --format-logs pino-pretty

Benefits:

• Works with any formatter that reads JSON lines from stdin (bunyan, pino-pretty, custom scripts)
• Preserves the Skybridge Ink UI (banner, tunnel info, TS errors, restart messages)
• Backward compatible — no behavior change when the flag is not passed
• Visible error in the UI if the formatter command is not found
• Safe against formatter crashes (EPIPE protection, falls back to raw output if formatter dies)

Implementation

I have a working implementation in #830 — happy to discuss the approach here first and rework the PR based on feedback.

This is what motivated the change: I’m using bunyan for structured logging in a Chift MCP server and wanted readable output in the dev CLI without losing the Skybridge UI features.

[pldesch-chift]

Moved to issue #835 to follow the repo convention of tracking features with issues. Closing this discussion.