install-plugins.sh: mktemp failure building CFG_SNAPSHOT now aborts
the install loudly (err + exit 1) instead of warning and continuing
UNGUARDED — a failed guard used to mean CLAUDE.md/.claude/settings.json/
settings.json could be silently rewritten by graphify's installer for
the rest of that run. Closes §3.4.
Added T5 to lib/tests/curated-config-guard.test.sh: extracts the
WIDER header block (GUARDED_CONFIGS through the closing `fi` — the
fail-closed logic lives in the top-level if/else, outside
restore_curated_configs(), so it needs its own awk range) in a
subshell with a stubbed `mktemp` forced to fail; asserts exit 1 and a
loud "mktemp failed" message. +2 assertions (4→6).
Verified: bash -n clean, shellcheck clean (both files), full `make
test` exit 0.
Bastien Chanot
999c7c475e