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).

config.ts

@@ -30,6 +30,9 @@ export const PATHS = {
 	 * Bounded self-contained snapshots (propositions + chains frozen at
 	 * creation), not append-only ledgers. */
 	practice: path.join(DATA_ROOT, "practice"),
+	/** Debug artifacts (env-gated): data/debug/provider-events/<chatId>.jsonl
+	 * raw provider stream recordings (src/agent/provider-events.ts). */
+	debug: path.join(DATA_ROOT, "debug"),
 } as const;
 
 // ─── Models ────────────────────────────────────────────────────────────────