refactor(natives): simplified native module loader and removed validation overhead

- Removed native binding validation function that checked required exports at load time.
- Enhanced native module loader to check XDG_DATA_HOME environment variable before ~/.omp/natives fallback.
- Removed dependency on @oh-my-pi/pi-utils from native module loader by inlining helper functions.
- Migrated child process termination from waitForChildProcess utility to killTree native binding.

packages/coding-agent/CHANGELOG.md

@@ -1,6 +1,7 @@
 # Changelog
 
 ## [Unreleased]
+
 ### Added
 
 - Chunk read formatting: `anchorStyle` (full / kind / bare), `read.anchorstyle` setting, and `chunked` flag on file display mode
@@ -25,6 +26,7 @@
 
 ### Removed
 
+- Removed `waitForChildProcess` utility (child process termination now handled by native `killTree` from pi-natives)
 - `grep-chunk.md` (folded into unified grep template)
 - `startMacAppearanceObserver` export (use `MacAppearanceObserver.start()`)
 - `copyToClipboard` export from pi-natives

packages/coding-agent/src/session/agent-session.ts

@@ -49,8 +49,8 @@ import {
 	modelsAreEqual,
 	parseRateLimitReason,
 } from "@oh-my-pi/pi-ai";
-import { MacOSPowerAssertion, type SearchDb } from "@oh-my-pi/pi-natives";
-import { abortableSleep, getAgentDbPath, isEnoent, logger } from "@oh-my-pi/pi-utils";
+import { killTree, MacOSPowerAssertion, type SearchDb } from "@oh-my-pi/pi-natives";
+import { abortableSleep, getAgentDbPath, isEnoent, logger, setNativeKillTree } from "@oh-my-pi/pi-utils";
 import type { AsyncJob, AsyncJobManager } from "../async";
 import type { Rule } from "../capability/rule";
 import { MODEL_ROLE_IDS, type ModelRegistry } from "../config/model-registry";
@@ -535,6 +535,8 @@ export class AgentSession {
 	}
 
 	constructor(config: AgentSessionConfig) {
+		setNativeKillTree(killTree);
+
 		this.agent = config.agent;
 		this.sessionManager = config.sessionManager;
 		this.settings = config.settings;

packages/coding-agent/src/utils/child-process.ts

@@ -1,88 +0,0 @@
-import type { ChildProcess } from "node:child_process";
-
-const EXIT_STDIO_GRACE_MS = 100;
-
-/**
- * Wait for a child process to terminate without hanging on inherited stdio handles.
- *
- * Daemonized descendants can inherit the child's stdout/stderr pipe handles. In that
- * case the child emits `exit`, but `close` can hang forever even though the original
- * process is already gone. We wait briefly for stdio to end, then forcibly stop
- * tracking the inherited handles.
- */
-export function waitForChildProcess(child: ChildProcess): Promise<number | null> {
-	const { promise, resolve, reject } = Promise.withResolvers<number | null>();
-
-	let settled = false;
-	let exited = false;
-	let exitCode: number | null = null;
-	let postExitTimer: NodeJS.Timeout | undefined;
-	let stdoutEnded = child.stdout === null;
-	let stderrEnded = child.stderr === null;
-
-	const cleanup = () => {
-		if (postExitTimer) {
-			clearTimeout(postExitTimer);
-			postExitTimer = undefined;
-		}
-		child.removeListener("error", onError);
-		child.removeListener("exit", onExit);
-		child.removeListener("close", onClose);
-		child.stdout?.removeListener("end", onStdoutEnd);
-		child.stderr?.removeListener("end", onStderrEnd);
-	};
-
-	const finalize = (code: number | null) => {
-		if (settled) return;
-		settled = true;
-		cleanup();
-		child.stdout?.destroy();
-		child.stderr?.destroy();
-		resolve(code);
-	};
-
-	const maybeFinalizeAfterExit = () => {
-		if (!exited || settled) return;
-		if (stdoutEnded && stderrEnded) {
-			finalize(exitCode);
-		}
-	};
-
-	const onStdoutEnd = () => {
-		stdoutEnded = true;
-		maybeFinalizeAfterExit();
-	};
-
-	const onStderrEnd = () => {
-		stderrEnded = true;
-		maybeFinalizeAfterExit();
-	};
-
-	const onError = (err: Error) => {
-		if (settled) return;
-		settled = true;
-		cleanup();
-		reject(err);
-	};
-
-	const onExit = (code: number | null) => {
-		exited = true;
-		exitCode = code;
-		maybeFinalizeAfterExit();
-		if (!settled) {
-			postExitTimer = setTimeout(() => finalize(code), EXIT_STDIO_GRACE_MS);
-		}
-	};
-
-	const onClose = (code: number | null) => {
-		finalize(code);
-	};
-
-	child.stdout?.once("end", onStdoutEnd);
-	child.stderr?.once("end", onStderrEnd);
-	child.once("error", onError);
-	child.once("exit", onExit);
-	child.once("close", onClose);
-
-	return promise;
-}