Correct Git freshness statuses and operational failure handling #220

Parent: #214

Train position: 6 of 26
Phase: P0 — Trustworthy runtime and release baseline

Problem

check_script_up_to_date can report success for a locally modified tracked script with no upstream, and unchecked Git failures can fall through to an “up to date” result. Deployment and self-update checks must never convert uncertainty into success.

Acceptance criteria

• Preserve the documented dirty status even when no upstream exists or remote comparison is skipped.
• Give dirty, behind, ahead, diverged, detached, missing-upstream, untracked, and not-in-repository states an explicit precedence table.
• Return a distinct operational failure for failed rev-list, fetch, repository discovery, or metadata commands; never report “up to date” after an unverified comparison.
• Keep warning text, stdout ownership, and statuses consistent between documentation and implementation.
• Add isolated tests for every state and for command, permission, malformed-repository, and network failures.
• Update examples and API documentation from the executable status table.

Dependencies

• None