Wave A: pi-native tool layer — delete LhTool/toPiTool, TypeBox everywhere, terminate on questions

- src/agent/lh-tool.ts deleted: the zod-wrapped LhTool + toPiTool bridge
  (z.toJSONSchema per call, clientQuestion flag, hand-rolled result mapping)
  is gone. Tools are pi-agent-core native AgentTools now.
- New src/agent/tool-execute.ts owns what the wrapper added: the abort guard
  (runWithAbortGuard: run signal + 30s per-call timeout + 250ms grace,
  'Operation aborted' / timeout wording preserved), ToolInputError (the
  retryable '- problem at path' format), result mapping (string verbatim /
  object JSON / image parts, details rides the record's tool part output),
  and questionResult() — placeholder + terminate:true (owner Option A:
  belt of terminate + slim makeQuestionStopper with the clean-question
  rule; maxTurns deleted from the teaching turn entirely per owner).
- All 11 tool files + tools.ts registries converted to TypeBox parameters
  (typebox@1.3.7, pinned to pi-agent-core's copy). zod refinements
  (quizInputProblems, askOptionProblems, live-nodeId) moved from schemas
  into execute — the model sees the same retryable error shape.
- question-core + contracts/probe TypeBox-authored (single source shared
  with the UI); tool-parts parse seam runs the boundary's full chain
  (Convert → Check → Clean → refinement), fixing the live-smoke lockout:
  pi's boundary Value.Converts correctAnswer: 17 → '17' but the record
  keeps raw args, so a parse without Convert rejected a posed quiz
  (invisible pending question, turn ended). Pinned with the real smoke
  emission shape.
- Subagents converted: demo-builder/researcher AgentTool-native,
  visual-maker/pdf-reader declaration-only pi-ai Tools with local execute
  fns, extraction submit schemas re-authored in TypeBox (owner option 2:
  zod defaults → Type.Optional + fill at the submit seam).
- Accepted delta, flagged: TypeBox-native schemas skip pi's JSON-Schema
  primitive coercion fast path... (boundary still Value.Converts), and
  prober-quiz unknown keys ride through (Value.Clean strips at display).
- Tests: 988 passing (was 967 at the recon baseline); tool-abort and
  read-tool rewritten against the native seams; question-core/question-
  tools/tool-parts/demos/web-search/graph-tools/plan-tree/probe-done/
  tool-toggles converted to Value.Check/execute pins.

Live smoke (PORT=3004, real model): native ls turn streams end-to-end; a
real quiz pose (first attempt missing correctAnswer → tool-input-error →
model retry → posed) terminates the turn cleanly and persists pending.

src/agent/subagents/visual-maker.ts

@@ -1,6 +1,5 @@
-import type { AssistantMessage, Message, ToolResultMessage, Usage } from "@earendil-works/pi-ai";
-import { z } from "zod";
-import { lhTool, piToolDeclarations, type LhTool } from "../lh-tool.ts";
+import type { AssistantMessage, Message, Tool, ToolResultMessage, Usage } from "@earendil-works/pi-ai";
+import { Type } from "typebox";
 import { piEngineFor, type PiEngine, type ThinkingLevel } from "../models.ts";
 import type { VisualResult } from "../../core/contracts.ts";
 import { getHeadless, type HeadlessApi } from "./headless.ts";
@@ -88,29 +87,32 @@ Your FINAL message: 1-2 sentences of notes for the teacher (what the figure show
 NEVER the SVG source itself. If you genuinely cannot make a correct picture of the brief, say exactly
 that in your final message and why.`;
 
-export function createVisualTools(): Record<string, LhTool<any, any>> {
+/** The wire declarations (pi-ai Tool, TypeBox parameters): this loop owns
+ *  execution itself — write/edit dispatch inline below, render feeds the
+ *  image-in-the-loop message — so the declarations carry no execute. */
+export function createVisualTools(): Record<string, Tool> {
 	return {
-		write_svg: lhTool({
+		write_svg: {
 			name: "write_svg",
 			description: "Write the complete SVG source for the figure (overwrites any previous version).",
-			schema: z.object({
-				svg: z.string().describe('Complete <svg xmlns="…">…</svg> markup.'),
+			parameters: Type.Object({
+				svg: Type.String({ description: 'Complete <svg xmlns="…">…</svg> markup.' }),
 			}),
-		}),
-		edit_svg: lhTool({
+		},
+		edit_svg: {
 			name: "edit_svg",
 			description:
 				"Replace one exact spot in the current SVG: old_text must appear EXACTLY ONCE and is replaced by new_text. Call write_svg first. For larger changes, write_svg the whole document.",
-			schema: z.object({
-				old_text: z.string().describe("The exact text to replace — must match exactly once in the current SVG."),
-				new_text: z.string().describe("The replacement text."),
+			parameters: Type.Object({
+				old_text: Type.String({ description: "The exact text to replace — must match exactly once in the current SVG." }),
+				new_text: Type.String({ description: "The replacement text." }),
 			}),
-		}),
-		render_svg: lhTool({
+		},
+		render_svg: {
 			name: "render_svg",
 			description: "Render the current SVG to a PNG and show it to you for inspection. No arguments.",
-			schema: z.object({}),
-		}),
+			parameters: Type.Object({}),
+		},
 	};
 }
 
@@ -130,7 +132,7 @@ export async function runVisualMaker(input: VisualMakerInput, opts: VisualMakerO
 	}
 
 	const tools = createVisualTools();
-	const toolDeclarations = piToolDeclarations(tools);
+	const toolDeclarations = Object.values(tools);
 	const engine = opts.engine ?? piEngineFor("visualMaker");
 	// BYOK (owner, 2026-09-22): the level rides the injected engine — no
 	// factory pin to consult (engine.level is the resolved/clamped value).
@@ -301,7 +303,7 @@ async function streamOnce(
 	engine: PiEngine,
 	systemPrompt: string,
 	messages: Message[],
-	tools: ReturnType<typeof piToolDeclarations>,
+	tools: Tool[],
 	reasoning: ThinkingLevel | undefined,
 	abortSignal?: AbortSignal,
 ): Promise<AssistantMessage> {