feat(coding-agent): removed context argument from eval agent() spawn

Shared background now flows through a '/Users/can/.omp/agent/sessions/-Projects-.tree-pi-commit/2026-06-10T15-36-32-782Z_019eb22d-970e-7000-8964-72c98becf3e8/local' file referenced in each prompt instead of a context string forwarded into the subagent's system prompt. The JS and Python preludes drop the context kwarg from agent(), the subagent system prompt drops the {{#if context}} block and the conversation-context file pointer, and runEvalAgent no longer writes a per-call conversation context file. AgentSession sheds the now-unused formatCompactContext() helper that supplied the file's body, and ToolSession.getCompactContext is removed alongside it.

packages/coding-agent/src/tools/index.ts

@@ -260,8 +260,6 @@ export interface ToolSession {
 	recordEvalSubagentUsage?: (output: number) => void;
 	/** Bridge to the connected client (e.g. ACP editor host). Tools should route fs/terminal/permission requests through this when available. */
 	getClientBridge?: () => ClientBridge | undefined;
-	/** Get compact conversation context for subagents (excludes tool results, system prompts) */
-	getCompactContext?: () => string;
 	/** Get cached todo phases for this session. */
 	getTodoPhases?: () => TodoPhase[];
 	/** Replace cached todo phases for this session. */