Fix mapfile for macOS default bash 3.2 (sync.sh, pull.sh)

[jackiexi1986-AI]

Problem

On macOS the default /bin/bash is 3.2 (3.2.57), which does not ship the mapfile/readarray builtin (bash 4+). Three call sites used mapfile -t ... < <(jq ...):

• scripts/sync.sh — jq branch, two places (group_names, paths). The script died with mapfile: command not found (exit 127) right before the grouped commits, so the sync never reached git push.
• scripts/pull.sh — one place (agent_rows, same jq + @tsv pattern). Identical failure when pulling per-agent rows.

bash -n does not catch this (it is a runtime missing-builtin, not a syntax error), and since scripts declare #!/usr/bin/env bash, on stock macOS they always run under bash 3.2.

Fix

Replace every mapfile -t arr < <(cmd) with the bash 3.2-compatible idiom:

arr=()
while IFS= read -r item; do arr+=("$item"); done < <(cmd)

Process substitution and while read both exist in bash 3.2, so behavior is unchanged on bash 4+/5.

Verification (macOS stock bash 3.2.57)

• /bin/bash -n scripts/sync.sh scripts/pull.sh scripts/nightly_sync.sh — clean.
• Full sync.sh chain against a scratch workspace + local bare remote: secret scan passed, per-group commits (core/skills/memory) plus the misc catch-all commit created and pushed — exit 0.
• scripts/nightly_sync.sh end-to-end against a real remote: export → secret scan → commit → git push -u origin main — exit 0.