feat: US-001 - Add buildImage helper to docker.ts and create SSH Dockerfile

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: NathanFlurry

packages/secure-exec/tests/e2e-docker/dockerfiles/sshd.Dockerfile

@@ -0,0 +1,10 @@
+FROM alpine:3.19
+RUN apk add --no-cache openssh \
+ && ssh-keygen -A \
+ && adduser -D -s /bin/sh testuser \
+ && echo "testuser:testpass" | chpasswd \
+ && sed -i 's/^#PasswordAuthentication.*/PasswordAuthentication yes/' /etc/ssh/sshd_config \
+ && sed -i 's/^#PermitEmptyPasswords.*/PermitEmptyPasswords no/' /etc/ssh/sshd_config \
+ && mkdir -p /home/testuser/upload
+EXPOSE 22
+CMD ["/usr/sbin/sshd", "-D", "-e"]

packages/secure-exec/tests/utils/docker.ts

@@ -8,6 +8,7 @@
 
 import { execFileSync, execSync } from "node:child_process";
 import { randomBytes } from "node:crypto";
+import path from "node:path";
 
 /* ------------------------------------------------------------------ */
 /*  Docker availability check                                         */
@@ -74,6 +75,20 @@ export interface Container {
 /*  Core implementation                                               */
 /* ------------------------------------------------------------------ */
 
+/**
+ * Build a Docker image from a Dockerfile and tag it.
+ */
+export function buildImage(dockerfilePath: string, tag: string): void {
+	if (!isDockerAvailable()) {
+		throw new Error("Docker is not available on this host");
+	}
+	execFileSync(
+		"docker",
+		["build", "-t", tag, "-f", dockerfilePath, path.dirname(dockerfilePath)],
+		{ stdio: "ignore", timeout: 120_000 },
+	);
+}
+
 /**
  * Pull an image if it is not already present locally.
  */