Implement context overflow compaction logic in session loop

Author: maxeonyx

packages/opencode/src/session/prompt.ts

@@ -33,6 +33,7 @@ import { spawn } from "child_process"
 import { Command } from "../command"
 import { $, fileURLToPath } from "bun"
 import { ConfigMarkdown } from "../config/markdown"
+import { Config } from "../config/config"
 import { SessionSummary } from "./summary"
 import { NamedError } from "@opencode-ai/util/error"
 import { fn } from "@/util/fn"