fix(SAC_LSTM_Bot): MA history self-truncation — read before > redirect; campaign v2 attempt-3 prep (#60)

$(cat f) inside a command redirected to f saw the already-truncated file,
so every eval cycle wiped ma_history_*.txt back to one leading-space value
and degraded the composite best-gate to last-cycle mean. Read is hoisted
into its own statement; unquoted expansion + tail -n keeps exactly the last
MA_WINDOW values. Verified: fresh/5+/6+ cycle edges reproduce sliding window.

SAC_LSTM_Bot/sac_train.sh

@@ -119,8 +119,16 @@ eval_checkpoint() {
     wr=$(( 100 * wins / rounds ))
     echo ">>> [eval] win rate: $wins/$rounds ($wr%) vs $opp"
     cat "$otmp" >> "$tmp"; rm -f "$otmp"
-    # Per-opponent history: append this cycle's win rate, keep last MA_WINDOW.
-    printf '%s\n' "$(cat "$(ma_hist_file "$opp")" 2>/dev/null)" "$wr" \
+    # Per-opponent history: append this cycle's win rate, keep last MA_WINDOW
+    # values on one line. Read FIRST, separately: `$(cat f)` inside a command
+    # redirected `> f` executes against the already-truncated file (bash sets
+    # up the redirect before running the substitution) — every cycle wiped the
+    # history back to a single leading-space value (#60). $hist is UNQUOTED on
+    # purpose: word-splitting turns the stored line into one value per line so
+    # tail keeps the last MA_WINDOW values.
+    local hist
+    hist="$(cat "$(ma_hist_file "$opp")" 2>/dev/null)"
+    printf '%s\n' $hist "$wr" \
       | tail -n "$MA_WINDOW" | tr '\n' ' ' > "$(ma_hist_file "$opp")"
   done
   mv "$tmp" "$EVAL_LOG_FILE"