Title: Inline compaction summary truncates lines to ~15 characters

Description

When a session is auto-compacted, the inline "Session Summary" embedded in the context stream clips every line to approximately 15 characters. Sections like "Constraints & Preferences", "Next Steps", and "Key Decisions" become unreadable. Example output:
Progress
Done

• [
• [x
• [
• [
• [x
  This happens because the compaction mechanism appears to apply a fixed-width truncation on each line rather than preserving the full text. The "compaction" config key (auto: true, tail_turns: 15) doesn't seem to control the summary generation behavior.

Plugins

compact tool

OpenCode version

1.18.9 (latest)

Steps to reproduce

compacting after a long task(used matt skills to break into tickets and compacting in between)

Screenshot and/or share link

Operating System

Windows x64

Terminal

windows terminal