feat: sanitize terminal control characters in the output package

[Vladislav Nechakhin (vladislav-nechakhin)]

Description

Text returned by the API is printed to the terminal as-is, so control characters in it are acted on by the terminal rather than displayed. This adds a printing API to internal/output that replaces those characters with a visible placeholder, and makes the existing renderers use it. Pretty output now shows U+FFFD in their place; JSON output is unchanged.

Key changes:

• New printers: Printf, Println, Fprintf, Fprintln, Errorf, Errorln.
• PrintLines/FprintLines for multi-line text such as encoded JSON.
• PrintProxied/FprintProxied for output another program produced, where escape sequences must pass through untouched.
• OutputTable, OutputTree and PrintRunsTable sanitize their titles, headers and cells; table rendering moved into a shared TableTo that takes a writer.
• TruncateRunes replaces the byte slice that shortened long run names, which could cut a multi-byte character in half.
• start_time is parsed instead of byte-sliced at fixed offsets, so an unexpected value renders as N/A.
• Titles underline to their rune count instead of their byte length.
• Dropped PrintError, which had no callers.