provider-events: raw provider stream recorder (LH_PROVIDER_EVENTS=1)

pi-ai 1.0's onProviderStreamEvent, at the layer our incident class lives
(GLM arg truncation, DeepSeek id resets) — env-gated (owner choice:
no app surface, off by default; raw events carry full prompts), one
JSONL per chat under data/debug/provider-events/ with a 20MB cap and a
run-start marker for record correlation.

Wired at every agent construction: teacher/prober turns (AgentBuildOptions.
chatId), jobs via LoopContext (researcher, demo-builder through
runSubagent; visual-maker + pdf-reader through their streamOnce), and
the extraction pipeline (extractor + auditor keyed by source id).
practice deliberately unwired (sunk-cost module).

src/agent/subagents/researcher.ts

@@ -71,6 +71,8 @@ export interface ResearcherRunOptions {
 	abortSignal?: AbortSignal;
 	onUsage?: (usage: Usage) => void;
 	onToolStart?: (toolName: string, args: unknown) => void;
+	/** Debug: raw provider-event recording key (LH_PROVIDER_EVENTS=1). */
+	chatId?: string;
 }
 
 /**
@@ -88,6 +90,7 @@ export async function runResearcherAgent(prompt: string, opts: ResearcherRunOpti
 		abortSignal: opts.abortSignal,
 		onUsage: opts.onUsage,
 		onToolStart: opts.onToolStart,
+		chatId: opts.chatId,
 	});
 	return text;
 }