TASK-IMP-096: Non-git installs state the ship-tasks git requirement

Summary

Install succeeds on a plain directory, and the only clue that the governance loop cannot run there is a hook line's aside. Say the quiet part in the summary: one line, printed only when .git is absent, naming what ship-tasks needs and the exact command to get it.

Problem

A consumer who installs into a non-git folder discovers the requirement at their first phase commit - the most expensive place to learn it.

Proposed Solution

In the summary block, when the repo has no .git: print cyberos install: this repo is not a git checkout - ship-tasks needs one; run: git init -b main && git add -A && git commit -m init. Git installs print nothing new.

Alternatives Considered

• Refuse to install without git. Rejected: install legitimately serves doc-only and evaluation uses; the loop is optional until tasks ship.
• Auto-run git init. Rejected: creating a repository is an operator decision (identity, default branch, what to commit), not an installer side effect.

Success Metrics

• Primary: a scratch non-git install prints exactly one such line and a git install prints none - suite-asserted every run. Baseline: only the hook aside exists. Deadline: final acceptance.
• Guardrail: the line names a command that works verbatim on a fresh directory.

Scope

In scope: the summary line, the hygiene scenario.

Out of scope / Non-Goals

• Any behavior change for git repos.
• Running git commands on the consumer's behalf.

Dependencies

• Shares install.sh with TASK-IMP-094/095 - one agent, serial.

AI Authorship Disclosure

• Tools used: Claude (Fable 5) running the CyberOS task-author skill inside Cowork.
• Scope: spec drafted from IMP-12; implementation under ship-tasks supervision.
• Human review: batch-4 PLAN approved 2026-07-17 (§0a); both HITL gates are recorded human verdicts.

1. Description (normative)

• 1.1 When the target repo has no .git, the install summary MUST include one line stating ship-tasks requires a git checkout and naming the verbatim remedy (git init -b main && git add -A && git commit -m init).
• 1.2 When the target is a git checkout, the summary MUST NOT include the line.
• 1.3 Coverage MUST land as a hygiene scenario running install against a non-git scratch directory (CYBEROS_NO_MIGRATE path acceptable) and a git one.

2. Acceptance criteria

• [ ] AC 1 (traces_to: #1.1, #1.3) - non-git scratch install shows the line once - test: tools/install/tests/test_install_hygiene.sh::t09_nongit_summary_line
• [ ] AC 2 (traces_to: #1.2) - git scratch install shows no such line - test: tools/install/tests/test_install_hygiene.sh::t09_nongit_summary_line (git arm)

3. Edge cases

• A git worktree or submodule dir where .git is a FILE, not a directory: counts as a git checkout (test uses git rev-parse semantics, not a -d .git probe - matching install.sh's own root detection).
• Bare-ish folders with a stale .git remnant: whatever git rev-parse --show-toplevel says is the truth the installer already uses; the line follows it.
• Security-class: none - one echo; no commands executed on the consumer's behalf.