[ancongui]

Trusted Codex and Claude CLI processes could terminate with SIGXFSZ when Python restored an inherited ignored signal under a finite POSIX file-size limit. Preserve the inherited disposition in that launch condition so an oversized write can return EFBIG while the kernel limit stays enforced. Unlimited parents, default signal dispositions and the separate untrusted command executor retain subprocess defaults. Process cleanup and typed outcome checks remain intact.

Prepare 0.2.27 metadata, release notes and all 448 canonical Studio captures. The original offending write and file remain unidentified. This change grants no additional attempt or budget reset and does not establish successful same-run recovery or generated-product acceptance.

Validation:

• Qualified implementation commit: 108 focused tests, four independent native checks, Ruff and mypy.
• Release preparation: 21 distribution, payload and release-note tests; compile; unchanged dependency locks; Studio TypeScript/build.
• Canonical walkthrough: 56 producers passed, 448 current fixture captures with matching hashes and viewports. Two representative desktop/mobile images reviewed directly.
• Strict documentation and social-card bounds; 94 documentation browser tests; five Pages browser tests.
• Offline wheel/sdist build, exact source/metadata/RECORD/legal/Studio checks and fresh installation outside the checkout, including the analytics extra.

The complete exact-head CI suite remains required before merge.