All three hooks changed shebang from bash to sh. No bashisms were in use
(no [[, no local, no arrays) so only the interpreter line moved. Verified
with sh -n, and dash smoke-run with a sample tool_input JSON.
All three hooks used `set -eu` + `cat | jq …`. Without jq installed, jq
would fail and `-e` would abort the hook → non-zero exit → Claude Code
refuses Edit/Write/Bash system-wide. Now each hook probes for jq BEFORE
`set -eu` and exits 0 silently if absent. Also dropped the useless `cat |`
pipe — `jq -r` reads stdin directly.
Companion: install.sh jq check upgraded from warn to hard `exit 1` because
without jq the hooks are dead weight; message states jq is required on
any machine that will activate the hooks.
