fix(codex): tolerate launcher stdout preambles

[KyleKincer]

Some CLI launchers write informational output to stdout before replacing themselves with codex app-server. Omarchy 4.0's standard omarchy-mise-install codex wrapper does this via mise use -g codex, causing the provider probe to fail at decode-wire-message even though Codex itself is current and functional.

This change lets child-process Codex clients ignore non-JSON lines only until the first valid JSON-RPC message is routed. Once protocol traffic begins, malformed stdout remains fatal. Ignored preamble diagnostics record only byte length rather than the launcher text.

Regression coverage verifies:

• an Omarchy/mise-style preamble no longer prevents initialization;
• child-process clients enable the behavior by default;
• malformed stdout after protocol startup still fails strictly.

Verification:

• vp test run packages/effect-codex-app-server/src/protocol.test.ts packages/effect-codex-app-server/src/client.test.ts
• vp run --filter effect-codex-app-server typecheck
• targeted vp fmt --check and vp lint

Implemented with GPT-5.6 Sol in Codex.

Note

Add ignoreNonJsonPreamble to CodexAppServerPatchedProtocol and default it on for child-process clients

• Introduces optional ignoreNonJsonPreamble on CodexAppServerPatchedProtocolOptions and CodexAppServerClientOptions; client.makeChildProcessClient sets it to true by default.
• In makeCodexAppServerPatchedProtocol, non-JSON lines before the first decoded message are skipped and logged as ignored_preamble; after the first message, non-JSON data still raises a CodexAppServerProtocolParseError.
• Adds tests in protocol.test.ts and client.test.ts, plus a mock-peer fixture flag CODEX_APP_SERVER_TEST_STDOUT_PREAMBLE.
• Behavioral Change: child-process clients now silently drop non-JSON stdout output emitted before the first protocol message; callers passing ignoreNonJsonPreamble: false to makeChildProcessClient can disable this.

^{Macroscope summarized b28f67d. (Automatic summaries will resume when PR exits draft mode or review begins).}

[macroscopeapp]

One convention finding: the new preamble handling uses Effect.catchTag, which the repo conventions replace with Effect.catchTags({ ... }) even for a single tag.

^{Posted via Macroscope — Effect Service Conventions}

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