fix(agent): make compaction timeout configurable

[nguyenha935]

Summary

• Add optional compaction timeout configuration for mid-loop compaction LLM calls.
• Increase the default timeout used by compaction from 30s to 120s for larger agent sessions.
• Expose the setting in agent defaults and per-agent compaction UI.

This is a clean replacement for #1151. The previous PR branch accidentally included an unrelated Discord commit; this branch is based on current upstream main and contains only the compaction timeout changes.

Verification

• Not run locally: this Tiny server does not currently have the Go toolchain installed (go: command not found).