Phase 2: single per-user box container for every thread

Every thread (agent turns + terminal + project commands) now execs into one
persistent per-user container (spoon-box-{username}) instead of ephemeral
docker run --rm — so the agent and terminal share the exact same running
environment, filesystem, and in-session installs.

- docker.ts: ensureUserContainer (persistent box) + streamExecInContainer/
  runExecInContainer (docker exec, streaming) sharing a factored streamSubprocess
- user-container.ts: reference-counted box lifecycle (held while any thread
  workspace is active or a terminal is connected; idle-reaped after
  SPOON_AGENT_BOX_IDLE_MS, default 30m)
- worker.ts: runClaim acquires the box; codex turn + runProjectCommand exec into
  it; release on stop/PR/failure
- terminal.ts: execs into the shared box (dockerode TTY) instead of a per-job
  container; materializeUserHome runs the dotfiles setup in the box
- Verified: agent + terminal run in the same box, share fs, dotfiles + tmux load

apps/agent-worker/src/runtime/docker.ts

@@ -1,4 +1,5 @@
 import path from 'node:path';
+import type { Readable } from 'node:stream';
 import { execa } from 'execa';
 
 import { env } from '../env';
@@ -225,6 +226,67 @@ export const execInWorkspaceContainer = async (args: {
   };
 };
 
+// Shared line-streaming + result normalization for a started subprocess
+// (used by both `docker run` and `docker exec` paths).
+type StreamingSubprocess = {
+  stdout: Readable | null;
+  stderr: Readable | null;
+} & Promise<{ exitCode?: number; shortMessage?: string; all?: string }>;
+
+const streamSubprocess = async (
+  subprocess: StreamingSubprocess,
+  redact: (value: string) => string,
+  onStdoutLine?: (line: string) => Promise<void>,
+  onStderrLine?: (line: string) => Promise<void>,
+): Promise<CommandResult> => {
+  let stdoutBuffer = '';
+  let stderrBuffer = '';
+  const output: string[] = [];
+  let lineHandlers = Promise.resolve();
+  const consume = async (
+    chunk: Buffer,
+    source: 'stdout' | 'stderr',
+    handler?: (line: string) => Promise<void>,
+  ) => {
+    output.push(chunk.toString('utf8'));
+    const next = `${source === 'stdout' ? stdoutBuffer : stderrBuffer}${chunk.toString('utf8')}`;
+    const lines = next.split(/\r?\n/);
+    const remainder = lines.pop() ?? '';
+    if (source === 'stdout') stdoutBuffer = remainder;
+    else stderrBuffer = remainder;
+    for (const line of lines) {
+      if (handler) await handler(redact(line));
+    }
+  };
+  subprocess.stdout?.on('data', (chunk: Buffer) => {
+    lineHandlers = lineHandlers.then(() =>
+      consume(chunk, 'stdout', onStdoutLine),
+    );
+  });
+  subprocess.stderr?.on('data', (chunk: Buffer) => {
+    lineHandlers = lineHandlers.then(() =>
+      consume(chunk, 'stderr', onStderrLine),
+    );
+  });
+  let result: Awaited<StreamingSubprocess>;
+  try {
+    result = await subprocess;
+  } catch (error) {
+    await lineHandlers;
+    const outputText = output.join('');
+    const message =
+      error instanceof Error ? error.message : 'Container command failed.';
+    return {
+      exitCode: 1,
+      output: redact(`${outputText}${outputText ? '\n' : ''}${message}`),
+    };
+  }
+  await lineHandlers;
+  if (stdoutBuffer && onStdoutLine) await onStdoutLine(redact(stdoutBuffer));
+  if (stderrBuffer && onStderrLine) await onStderrLine(redact(stderrBuffer));
+  return normalizeRunResult(result, output.join(''), redact);
+};
+
 export const streamInJobContainer = async (args: {
   workdir: string;
   containerHome?: string;
@@ -262,58 +324,110 @@ export const streamInJobContainer = async (args: {
       timeout: args.timeoutMs,
     },
   );
-  let stdoutBuffer = '';
-  let stderrBuffer = '';
-  const output: string[] = [];
-  let lineHandlers = Promise.resolve();
-  const consume = async (
-    chunk: Buffer,
-    source: 'stdout' | 'stderr',
-    handler?: (line: string) => Promise<void>,
-  ) => {
-    output.push(chunk.toString('utf8'));
-    const next = `${source === 'stdout' ? stdoutBuffer : stderrBuffer}${chunk.toString('utf8')}`;
-    const lines = next.split(/\r?\n/);
-    const remainder = lines.pop() ?? '';
-    if (source === 'stdout') stdoutBuffer = remainder;
-    else stderrBuffer = remainder;
-    for (const line of lines) {
-      if (handler) {
-        await handler(args.redact(line));
-      }
-    }
-  };
-  subprocess.stdout.on('data', (chunk: Buffer) => {
-    lineHandlers = lineHandlers.then(() =>
-      consume(chunk, 'stdout', args.onStdoutLine),
-    );
-  });
-  subprocess.stderr.on('data', (chunk: Buffer) => {
-    lineHandlers = lineHandlers.then(() =>
-      consume(chunk, 'stderr', args.onStderrLine),
-    );
-  });
-  let result: Awaited<typeof subprocess>;
-  try {
-    result = await subprocess;
-  } catch (error) {
-    await lineHandlers;
-    const outputText = output.join('');
-    const message =
-      error instanceof Error ? error.message : 'Container command failed.';
-    return {
-      exitCode: 1,
-      output: args.redact(`${outputText}${outputText ? '\n' : ''}${message}`),
-    };
-  }
-  await lineHandlers;
-  if (stdoutBuffer && args.onStdoutLine) {
-    await args.onStdoutLine(args.redact(stdoutBuffer));
-  }
-  if (stderrBuffer && args.onStderrLine) {
-    await args.onStderrLine(args.redact(stderrBuffer));
-  }
-  return normalizeRunResult(result, output.join(''), args.redact);
+  return streamSubprocess(
+    subprocess,
+    args.redact,
+    args.onStdoutLine,
+    args.onStderrLine,
+  );
+};
+
+// Per-user persistent "box" container that all of a user's threads exec into
+// (Phase 2). Started once, reused; the home volume persists state across stops.
+export const userContainerName = (username: string) =>
+  `spoon-box-${username.replace(/[^a-zA-Z0-9_.-]/g, '-')}`;
+
+export const ensureUserContainer = async (args: {
+  username: string;
+  workdir: string;
+  containerHome: string;
+}): Promise<string> => {
+  await ensureJobImagePulled();
+  const name = userContainerName(args.username);
+  const inspect = await execa(
+    containerRuntime(),
+    ['inspect', '-f', '{{.State.Running}}', name],
+    { reject: false, stdin: 'ignore' },
+  );
+  if (inspect.exitCode === 0 && inspect.stdout.trim() === 'true') return name;
+  // Not running: remove any stale container, then start fresh.
+  await execa(containerRuntime(), ['rm', '-f', name], { reject: false });
+  await execa(
+    containerRuntime(),
+    [
+      'run',
+      '-d',
+      '--name',
+      name,
+      '--memory',
+      '4g',
+      '--cpus',
+      '2',
+      ...networkArgs(),
+      '-v',
+      jobWorkspaceVolumeSpec(args.workdir, args.containerHome),
+      '-w',
+      args.containerHome,
+      env.jobImage,
+      'sleep',
+      'infinity',
+    ],
+    { stdin: 'ignore' },
+  );
+  return name;
+};
+
+export const streamExecInContainer = async (args: {
+  containerName: string;
+  command: string[];
+  environment: Record<string, string>;
+  containerCwd: string;
+  redact: (value: string) => string;
+  timeoutMs: number;
+  onStdoutLine?: (line: string) => Promise<void>;
+  onStderrLine?: (line: string) => Promise<void>;
+}): Promise<CommandResult> => {
+  const subprocess = execa(
+    containerRuntime(),
+    [
+      'exec',
+      ...environmentArgs(args.environment),
+      '-w',
+      args.containerCwd,
+      args.containerName,
+      ...args.command,
+    ],
+    { all: true, reject: false, stdin: 'ignore', timeout: args.timeoutMs },
+  );
+  return streamSubprocess(
+    subprocess,
+    args.redact,
+    args.onStdoutLine,
+    args.onStderrLine,
+  );
+};
+
+export const runExecInContainer = async (args: {
+  containerName: string;
+  command: string[];
+  environment: Record<string, string>;
+  containerCwd: string;
+  redact: (value: string) => string;
+  timeoutMs: number;
+}): Promise<CommandResult> => {
+  const result = await execa(
+    containerRuntime(),
+    [
+      'exec',
+      ...environmentArgs(args.environment),
+      '-w',
+      args.containerCwd,
+      args.containerName,
+      ...args.command,
+    ],
+    { all: true, reject: false, stdin: 'ignore', timeout: args.timeoutMs },
+  );
+  return normalizeRunResult(result, result.all, args.redact);
 };
 
 export const stopWorkspaceContainer = async (containerName: string) => {