Feature request: compact-on-exit setting and app:compact keybinding action

Problem

There's no way to compact and exit a session as a single action. /compact and /exit are harness primitives that can't be invoked from custom commands, skills, hooks, agents, or keybindings.

Typing /compact then waiting then /exit works, but chaining them (e.g. /compact ; /exit) quits without compacting.

Requested features (either would solve it)

1. compactOnExit setting (boolean): automatically compact the conversation before exiting. Analogous to how autoCompact triggers compaction at a context threshold.

1. app:compact keybinding action: expose compact as a bindable action so users can create key chords (e.g. ctrl+k ctrl+q bound to compact, then exit). Currently the keybindings action list has no compact equivalent.

Context

• autoCompact (threshold-based) exists and works well for mid-session compaction
• But there's no way to ensure compaction happens at session end
• Custom commands can't reach harness primitives, so workarounds via the plugin system are impossible
• Users who --continue sessions lose context when they exit without compacting

Workaround

Currently using autoCompact: 0.5 for aggressive mid-session compaction, plus a custom /ciao command that saves context to memory files before exit. This preserves context for fresh sessions but doesn't help --continue workflows.