fix(brief): avoid bash 3.2 parse error from apostrophe in heredoc

[RevazBakuradze]

Problem

bin/fm-brief.sh fails to parse under the bash that ships with macOS (GNU bash 3.2.57, still the default /bin/bash). The script's shebang is #!/usr/bin/env bash, so on a stock macOS machine it runs under 3.2 and dies before doing anything:

$ bash -n bin/fm-brief.sh
bin/fm-brief.sh: line 211: unexpected EOF while looking for matching `''
bin/fm-brief.sh: line 263: syntax error: unexpected end of file

The cause is a bash 3.2 parser bug: a lone single quote (apostrophe) inside a here-doc that is nested in a command substitution (VAR=$(cat <<EOF ... EOF)) is mis-parsed as the start of a single-quoted string that never closes. Line 211, inside the no-mistakes DOD=$(cat <<EOF ...) block, contains no-mistakes', which trips it. Bash 4+ parses the same construct correctly, so this only affects users on the stock macOS bash.

Minimal repro:

cat > /tmp/repro.sh <<'OUTER'
X=$(cat <<EOF
no-mistakes' own guidance
EOF
)
OUTER
bash -n /tmp/repro.sh   # 3.2: "unexpected EOF while looking for matching `''"; 4+: clean

Fix

Rephrase that one line to remove the lone apostrophe (no escaping, keeps it readable):

Follow no-mistakes' own guidance for the mechanics: -> Follow the no-mistakes guidance for the mechanics:

One line changed; no behavior change. It is the only lone apostrophe inside any of the script's $(cat <<EOF ...) blocks.

Verification

• Before: bash -n bin/fm-brief.sh -> 2 errors (under bash 3.2.57).
• After: bash -n bin/fm-brief.sh -> clean (exit 0), and scaffolding still produces valid briefs.