Write apikey-mode auth.json so Codex CLI 0.122+ can authenticate via OPENAI_API_KEY (#5276)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies
> - The Codex adapter spawns the OpenAI Codex CLI to drive the model
> - Codex CLI 0.122 changed how it reads credentials: it ignores
`OPENAI_API_KEY` from the environment and reads only
`$CODEX_HOME/auth.json`
> - Without auth.json, Codex 0.122+ returns 401 "Missing bearer or basic
authentication" on `/v1/responses` even when `OPENAI_API_KEY` is
forwarded into the sandbox or remote shell
> - This pull request materializes an apikey-mode `auth.json` in the
managed Codex home (or per-run for the test probe) when an
`OPENAI_API_KEY` is configured
> - The benefit is configured Codex API keys authenticate correctly with
current Codex CLI versions across local, SSH, and sandbox targets

## What Changed

- `codex-home.ts`: add `writeApiKeyAuthJson()` and let
`prepareManagedCodexHome` accept an `apiKey` override that replaces the
symlinked host auth.json with an apikey-mode file
- `execute.ts`: pass `envConfig.OPENAI_API_KEY` into
`prepareManagedCodexHome` so the managed (and synced-to-remote) Codex
home authenticates via the configured key
- `test.ts`: when `OPENAI_API_KEY` is available, wrap the hello probe
with a small shell that materializes a per-run `$CODEX_HOME/auth.json`
before exec'ing codex; key content rides through env to avoid leaking
into process listings
- Update the `codex_hello_probe_auth_required` hint to explain Codex CLI
does not read `OPENAI_API_KEY` from env

## Verification

- `pnpm vitest run --no-coverage --project
@paperclipai/adapter-codex-local`
- `pnpm typecheck` clean
- Manual: Codex 0.122.0 with empty `CODEX_HOME` returns 401 with
env-only auth; with this change it authenticates cleanly

## Risks

Low risk — when no API key is configured, behavior is unchanged (no
auth.json written, existing chatgpt-mode flow preserved). Apikey-mode
`auth.json` is the upstream-supported format.

## Model Used

Claude Opus 4.7 (1M context)

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] If this change affects the UI, I have included before/after
screenshots — N/A (no UI)
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

packages/adapters/codex-local/src/server/execute.ts

@@ -332,8 +332,16 @@ export async function execute(ctx: AdapterExecutionContext): Promise<AdapterExec
   const codexSkillEntries = await readPaperclipRuntimeSkillEntries(config, __moduleDir);
   const desiredSkillNames = resolveCodexDesiredSkillNames(config, codexSkillEntries);
   await ensureAbsoluteDirectory(cwd, { createIfMissing: true });
+  const configuredOpenAiApiKey =
+    typeof envConfig.OPENAI_API_KEY === "string" && envConfig.OPENAI_API_KEY.trim().length > 0
+      ? envConfig.OPENAI_API_KEY.trim()
+      : null;
   const preparedManagedCodexHome =
-    configuredCodexHome ? null : await prepareManagedCodexHome(process.env, onLog, agent.companyId);
+    configuredCodexHome
+      ? null
+      : await prepareManagedCodexHome(process.env, onLog, agent.companyId, {
+          apiKey: configuredOpenAiApiKey,
+        });
   const defaultCodexHome = resolveManagedCodexHomeDir(process.env, agent.companyId);
   const effectiveCodexHome = configuredCodexHome ?? preparedManagedCodexHome ?? defaultCodexHome;
   await fs.mkdir(effectiveCodexHome, { recursive: true });