fix(server): Codex V2 sessions expand ~ in the binary path

[juliusmarminge]

Stacked on #13467.

A Codex binary path like ~/bin/codex passed the provider readiness probe, but every real V2 session then failed to spawn. CodexDriver builds the probe's settings with binaryPath: expandHomePath(config.binaryPath). createCodexAdapterV2 spread the raw config into the adapter's settings and fixed up only homePath, so the app-server spawn got the literal ~/bin/codex. Child processes don't get shell expansion.

Change

createCodexAdapterV2 now sets binaryPath: expandHomePath(config.binaryPath) where it builds the adapter's settings, next to the existing homePath resolution. It uses the same helper the driver uses.

Verification

• New test in CodexAdapterV2.test.ts ("expands ~ in the configured binary path before spawning"). It builds the adapter through createCodexAdapterV2 with binaryPath: "~/bin/codex" and the real codexAppServerClientFactoryFromSettingsLayer, opens a session, and asserts that a recording spawner saw <homedir>/bin/codex.
• Revert check: without the fix, the test fails with expected [ '~/bin/codex' ] to deeply equal [ '/home/julius/bin/codex' ].
• vp test run src/orchestration-v2/Adapters/CodexAdapterV2.test.ts: 115 passed.
• vp exec tsc --noEmit -p . in apps/server: no errors.
• vp lint on the two touched files: no new warnings. The two existing unused-variable warnings in CodexAdapterV2.ts are unrelated.
• Not run: repo-wide checks, and a live Codex run. The test already records the exact spawn command.

Model: Claude Opus 5.5 (Claude Code)

🤖 Generated with Claude Code

---

[macroscopeapp]

Approvability

Verdict: Approved at b055608

Macroscope's review found this PR approvable — This narrowly scoped fix normalizes home-relative Codex V2 binary paths before process spawning, while preserving existing behavior for other paths. Focused regression coverage verifies the exact executable passed to the spawner, and no product defaults or static-analysis suppressions are changed.

Notes:

• No code objects were reviewed. Approvability was decided on eligibility alone.

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[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

ℹ️ No successful main baseline artifact is available yet. This run establishes the initial measurement.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	—	4.9 KiB	—	6.8 KiB	✅
Codex	Thread snapshot wire	—	3.7 KiB	—	4.9 KiB	✅
Codex	Live turn WebSocket wire	—	1.2 KiB	—	2.0 KiB	✅
Codex	Live turn WebSocket decoded	—	20.4 KiB	—	29.3 KiB	✅
Codex	Live turn messages	—	2	—	8	✅
Claude	Total thread wire	—	4.9 KiB	—	6.8 KiB	✅
Claude	Thread snapshot wire	—	3.7 KiB	—	4.9 KiB	✅
Claude	Live turn WebSocket wire	—	1.2 KiB	—	2.0 KiB	✅
Claude	Live turn WebSocket decoded	—	20.8 KiB	—	29.3 KiB	✅
Claude	Live turn messages	—	2	—	8	✅

Baseline: unavailable · PR result: d5fbd4f · Source CI: failure

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 106.1 KiB
• Claude decoded thread snapshot: 106.4 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.