fix(codex): show affected paths in file approval requests

[rynfar]

Codex file-change approval requests sometimes omit a reason, leaving the card without useful detail. Use the supplied file operations and paths, or the write root, when no reason is available. Keep explicit reasons and bound the file list to 20 entries plus a remaining count.

Adopts upstream #8669, 57a6b70e24221f00c9a161f1e5b6b2ddd753bc8f. Existing approval decisions and wire contracts are unchanged.

Validation: 78 Codex adapter/session-runtime tests, server typecheck, and targeted lint pass.

Integrated browser verification: the actual Pylon approval card renders synthetic payloads matching the adapter’s old empty detail and new sorted file-change fallback. No approval was submitted. The adapter tests verify the provider-to-detail mapping.

Before:

After:

Model: GPT-6 Astra. Harness: Codex.

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.6 KiB	13.8 KiB	+173 B (+1.2%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.1 KiB	7.1 KiB	−3 B (−0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.5 KiB	6.7 KiB	+176 B (+2.6%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	56.5 KiB	57.4 KiB	+910 B (+1.6%)	66.4 KiB	✅
Codex	Live turn messages	8	10	+2 (+25.0%)	21	✅
Claude	Total thread wire	13.7 KiB	13.8 KiB	+184 B (+1.3%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.1 KiB	7.1 KiB	−1 B (−0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.6 KiB	6.7 KiB	+185 B (+2.8%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.3 KiB	58.2 KiB	+928 B (+1.6%)	66.4 KiB	✅
Claude	Live turn messages	8	10	+2 (+25.0%)	21	✅

Baseline: 6466561 · PR result: d77a435 · Source CI: success

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: 111.2 KiB
• Claude decoded thread snapshot: 111.9 KiB

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