v0.9.2

Infinite sessions (#116)

• New infiniteSessions global config flag (defaults to false) enables SDK automatic context compaction for long-lived channel sessions
• Background compaction at 80% context window usage, blocking at 95%
• Hot-reloadable: config changes take effect on next session create/resume
• Debug logging for session.usage_info and session.compaction_start/complete events with token metrics