Split fetch from jobsearch into a separate fetcher command, and renamed fetch once to fts-once

job-search no longer has a fetch command. Its subcommands are now in
cmd/fetcher, which reads the same configuration: "fetcher service" runs
every enabled source's fetcher on its interval until stopped, and
"fetcher fts-once" (was "fetch once") fetches from Find a Tender once and
prints the releases as JSON. The new namea say what the commands do,
because service runs every source while fts-once fetches only from Find a
Tender.

The code stays in internal/cli/fetch, where NewCommands replaces the fetch
parent command. once.go is now fts_once.go and commandOnce is
commandFTSOnce. The README's usage, the config README and the find_a_tender
api_root comment now give the new command names.

cmd/fetcher/main.go

@@ -0,0 +1,82 @@
+/*
+Copyright © 2026 Craig Williams <craig@avsdev.uk>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+// Command fetcher, for fetching opportunities from JobSearch's sources. Run
+// `fetcher --help` for usage.
+package main
+
+import (
+	"fmt"
+	"log/slog"
+	"os"
+	"strings"
+
+	"github.com/spf13/cobra"
+
+	"git.avsdev.uk/Go/job-search/internal/cli"
+	"git.avsdev.uk/Go/job-search/internal/cli/fetch"
+)
+
+// newRootCmd builds the command tree. It returns a fresh tree on each call so
+// tests can run commands in isolation.
+func newRootCmd() *cobra.Command {
+	opts := &cli.Options{}
+
+	root := &cobra.Command{
+		Use:   "fetcher",
+		Short: "Fetch tools for JobSearch",
+		Long: `fetcher fetches from Find a Tender once and prints the releases as
+JSON (fts-once), or polls every enabled source on its interval until stopped
+(service). It reads the JobSearch configuration.
+	`,
+		SilenceUsage:  true, // don't print usage on runtime errors
+		SilenceErrors: true, // main prints the error once
+		CompletionOptions: cobra.CompletionOptions{
+			HiddenDefaultCmd: true,
+		},
+		PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
+			cli.SetupInitialLogging(cmd)
+
+			slog.Debug("command persistent pre-run", "command", "root")
+			slog.Debug(
+				"command",
+				"path", strings.Join(strings.Split(cmd.CommandPath(), " ")[1:], " "),
+			)
+
+			return nil
+		},
+		PersistentPostRunE: func(cmd *cobra.Command, args []string) error {
+			slog.Debug("command persistent post-run", "command", "root")
+
+			return opts.Finish()
+		},
+	}
+
+	cobra.EnableTraverseRunHooks = true
+
+	opts.Bind(root)
+
+	root.AddCommand(fetch.NewCommands(opts)...)
+
+	return root
+}
+
+func main() {
+	if err := newRootCmd().Execute(); err != nil {
+		fmt.Fprintln(os.Stderr, "fetcher:", err)
+		os.Exit(1)
+	}
+}

cmd/fetcher/main_test.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"slices"
+	"testing"
+)
+
+// The commands are tested in internal/cli/fetch. This test checks newRootCmd
+// puts them together.
+
+func TestCommandTree(t *testing.T) {
+	root := newRootCmd()
+
+	var names []string
+	for _, c := range root.Commands() {
+		names = append(names, c.Name())
+	}
+
+	for _, want := range []string{"fts-once", "service"} {
+		if !slices.Contains(names, want) {
+			t.Errorf("fetcher has no %q command; has %v", want, names)
+		}
+	}
+
+	for _, flag := range []string{"config", "debug", "quiet"} {
+		if root.PersistentFlags().Lookup(flag) == nil {
+			t.Errorf("fetcher has no --%s flag", flag)
+		}
+	}
+}