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/tools/find.ts

@@ -1,7 +1,8 @@
 import * as fs from "node:fs/promises";
 import * as path from "node:path";
-import { z } from "zod";
-import { lhTool } from "../lh-tool.ts";
+import { Type } from "typebox";
+import type { AgentTool } from "@earendil-works/pi-agent-core";
+import { serverExecute } from "../tool-execute.ts";
 import {
 	capOutput,
 	formatSize,
@@ -23,20 +24,21 @@ import {
 
 const DEFAULT_LIMIT = 1000;
 
-const findInputSchema = z.object({
-	pattern: z
-		.string()
-		.min(1)
-		.describe("Glob pattern to match files, e.g. '*.ts', '**/*.json', or 'src/**/*.spec.ts'"),
-	path: z.string().optional().describe("Directory to search in (default: the learner's home directory)"),
-	limit: z.number().int().positive().optional().describe("Maximum number of results (default: 1000)"),
+const findInput = Type.Object({
+	pattern: Type.String({
+		minLength: 1,
+		description: "Glob pattern to match files, e.g. '*.ts', '**/*.json', or 'src/**/*.spec.ts'",
+	}),
+	path: Type.Optional(Type.String({ description: "Directory to search in (default: the learner's home directory)" })),
+	limit: Type.Optional(Type.Integer({ description: "Maximum number of results (default: 1000)" })),
 });
 
-export const findTool = lhTool({
+export const findTool: AgentTool<typeof findInput> = {
 	name: "find",
+	label: "find",
 	description: `Search for files by glob pattern. Returns matching file paths relative to the search directory. Ignores node_modules, .git, and Library directories. Output is truncated to ${DEFAULT_LIMIT} results or ${formatSize(MAX_OUTPUT_BYTES)} (whichever is hit first).`,
-	schema: findInputSchema,
-	async execute(input, ctx) {
+	parameters: findInput,
+	execute: serverExecute("find", findInput, async (input, ctx) => {
 		if (ctx?.signal?.aborted) return "Operation aborted";
 		const searchPath = resolveSourcePath(input.path);
 		let stat;
@@ -81,5 +83,5 @@ export const findTool = lhTool({
 		if (truncated) notices.push(`${formatSize(MAX_OUTPUT_BYTES)} limit reached`);
 		if (timedOut) notices.push("search timed out after 10s — partial results, narrow the directory");
 		return notices.length > 0 ? `${content}\n\n[${notices.join(". ")}]` : content;
-	},
-});
+	}),
+};