The agent/ package is now session/ — because a session is the
top-level concept. The package contains:
- harness: implements Core, the session orchestrator
- Agent: the reasoning entity (history, runtime, tools)
- History: conversation accumulator
- Fifo, loop, compaction, hooks, commands
The old session/ package (which just held extracted fields) is
dissolved back into the harness. One package, clean ownership.