feat(go): add --print-fio-table flag to fuj sync --dry-run

Prints an aligned tabwriter table of every Fio transaction in the
look-back window, with a STATUS column showing NEW (would be appended)
or DUP (already in sheet). Only fires when --dry-run is also set, so
it can't affect real syncs. Refactors Sync ID computation into a single
pre-pass shared by both the table printer and the row builder.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

go/internal/services/banksync/fio_table.go

@@ -0,0 +1,32 @@
+package banksync
+
+import (
+	"fmt"
+	"io"
+	"text/tabwriter"
+
+	"fuj-management/go/internal/io/fio"
+)
+
+func printFioTable(w io.Writer, txns []fio.Transaction, syncIDs []string, existing map[string]bool) {
+	tw := tabwriter.NewWriter(w, 0, 0, 2, ' ', 0)
+	fmt.Fprintln(tw, "DATE\tAMOUNT\tSENDER\tVS\tMESSAGE\tBANKID\tSTATUS")
+	for i, tx := range txns {
+		status := "NEW"
+		if existing[syncIDs[i]] {
+			status = "DUP"
+		}
+		fmt.Fprintf(tw, "%s\t%.2f\t%s\t%s\t%s\t%s\t%s\n",
+			tx.Date, tx.Amount, tx.Sender, tx.VS,
+			truncRunes(tx.Message, 40), tx.BankID, status)
+	}
+	_ = tw.Flush()
+}
+
+func truncRunes(s string, n int) string {
+	rs := []rune(s)
+	if len(rs) <= n {
+		return s
+	}
+	return string(rs[:n-1]) + "…"
+}