feat(agent-core): throttle goal continuation turns when waiting for background agents

When running in goal mode with a swarm of background agents, the driveGoal() loop currently schedules continuation turns with no minimum interval. The model calls TaskList every 1-2 seconds to check agent status, consuming 100-200 tokens per turn and wasting a large amount of context over a long-running goal.

We fixed this in our fork by adding a 15-second minimum interval between goal continuation turns and by updating the goal reminder/continuation prompt to tell the model not to poll background tasks with TaskList (prefer automatic completion notifications or TaskOutput(block=true)).

Commit with the fix: https://github.com/thecannabisapp/kimi-code/commit/f227bb20

If the maintainers want to merge this, the key changes are in packages/agent-core/src/agent/turn/index.ts (the driveGoal throttle) and packages/agent-core/src/agent/injection/goal.ts (the prompt guidance).

Start with driveGoal in packages/agent-core/src/agent/turn/index.ts and the goal reminder and continuation prompt in packages/agent-core/src/agent/injection/goal.ts. Compare the referenced commit f227bb20 with the current files, then verify that goal continuation turns have a 15-second minimum interval and that the prompt directs the model away from TaskList polling toward completion notifications or TaskOutput(block=true).