Prettify + make actionable vp run error output (missing task)

[linear]

Context

• Discord thread: https://discord.com/channels/1138376133969203262/1479003656018858004
• Screenshot: https://cdn.discordapp.com/attachments/1426407740049457233/1479003655599296593/CleanShot_2026-03-05_at_15.32.192x.png

Current behavior

• Running vp run ship fails with an error like:

[Vite+] run error: [Error: Failed to plan tasks from `vp run build` in task @nkzw/fate-private#ship

Caused by:
    Task "build" not found] {
  code: 'GenericFailure'
}

Problem

• Output is technically correct but hard to scan and not very actionable.

Proposal / UX goals

• One-line, human-friendly summary up top (e.g. "Task 'build' not found")
• Clearly show where the missing task was referenced (e.g. @nkzw/fate-private#ship depends on build)
• Suggest next steps / commands (pick the real ones):
  • show available tasks (e.g. vp run --list / vp list)
  • hint where tasks come from (vite.config.ts / vp config / package.json scripts)
• Keep the raw error + code available behind --verbose or as a secondary block.

Acceptance criteria

• Improved formatting for missing-task errors (colors + structure)
• Add actionable suggestions in default output
• Preserve current debug info in verbose mode

[linear]

VP-223