test: eliminate SIGPIPE flake in grep-q assertions (fixes intermittent CI)

[aimsise]

Problem

The Tests CI job failed intermittently with a FALSE assertion failure — most recently test-post-ship-state-auto-compact.sh AC-2: serial early-exit guarded by the off branch, where the substring was present but the assertion reported FAIL. The CI log showed the tell:

tests/test-post-ship-state-auto-compact.sh: line 84: printf: write error: Broken pipe
  FAIL AC-2: serial early-exit guarded by the off branch

Root cause (SIGPIPE under pipefail): assert_contains / assert_not_contains (duplicated in 5 files) and many inline checks used:

printf '%s' "$haystack" | grep -qF -- "$needle"   # under set -euo pipefail

With a large (file-sized) $haystack, printf writes in stdio chunks; grep -q matches early and exits, closing the pipe; printf's next write gets SIGPIPE → exits 141 → pipefail makes the whole pipeline non-zero → the assertion falsely fails even though the match is correct. Timing-dependent, so the same test code passed on the v10.0.0 and PR #100 runs and broke this one.

Fix

Convert every racy 2-stage producer | grep -q… to a pipe-free, SIGPIPE-safe equivalent (behavior-preserving — grep -q's found/not-found is identical, and a here-string never changes a substring/line match):

printf '%s' "$X" | grep -q… -- "$N"   ->   grep -q… -- "$N" <<<"$X"
cat FILE          | grep -q… "$N"     ->   grep -q… -- "$N" FILE
CMD               | grep -q… "$N"     ->   h=$(CMD); grep -q… -- "$N" <<<"$h"

323 occurrences across 30 test files, including all 5 assert_contains + 3 assert_not_contains definitions + assert_blocked_message. grep flags (-qF/-qE/-qiF/-qx) preserved; -- added before patterns.

Left untouched (not racy): non--q grep (grep -c / grep -o, read to EOF — no early-exit race), multi-stage pipes, and short bounded producers (head -1).

Independent of the v10.0.0 / swap-headroom changes (the swap fix touched only the ShellCheck CI job; this touches only tests/).

Verification

• tests/run-all.sh ALL TEST SUITES PASSED — every suite's pass count byte-identical to baseline (test-skill-contracts 915/915, test-path-consistency 145/145, test-ask-guard 56/56, …).
• shellcheck --severity=warning clean (CI match) — the 323 conversions introduce no warning.
• Only tests/ touched (no agents / hooks / skills). Each edited file independently re-ran green (or bash -n for the two claude -p files).

🤖 Generated with Claude Code

https://claude.ai/code/session_01Mw2bH4wbEPeebXsvSG6rWe