feat: make the update source one repository address, the official repo by default

The update source used to be three things - a remote name or an address, plus an
optional branch - and unset it followed whatever this directory's remotes and
upstream happened to say. That asked people to understand git topology before
they could update, and the person it was built for could not tell what "follow
the remote this tree tracks" meant. It is now one field: config.yaml update.repo,
an address, empty meaning the official repository
(https://github.com/AIPentest/CyberStrikeAI.git). Point it at a mirror (GitHub is
hard to reach in some places) or at your own fork and that is the whole
configuration.

The branch nothing is any more: an update follows the source repository's own
default branch, resolved from the source itself (ls-remote --symref HEAD), so a
fork whose default is not "main" still works and nobody has to name a branch.
Remote names, the mine/origin/upstream ranking, @{upstream} tracking and the
adopt flow's branch argument are all gone with it.

The console page loses two input fields: the source section is one address, a
hint that empty means the official repository, and a save button; clearing the
address is the way back to the default. The install facts drop the remote name,
the check section shows the source's default branch once the network answer
arrives, and the adopt entry no longer requires saving an address first - the
official default makes connecting a tarball install a zero-configuration action.

The CLI now reads the same update.repo field the page saves (LoadUpdateRepo reads
just that field, without validating the rest of the file - a broken unrelated
section must not block the path that fixes the tree), so the keyboard and the
button cannot update from different repositories. -check-update prints the source
it is about to use.

Tests: the source suite now pins the default (official), the single-address save
(including the empty-string reset), and that the followed branch comes from the
source's own default branch rather than a hardcoded "main"; the console suite
posts the one field and renders the default hint; docs, config.example.yaml and
upgrade.sh describe the one-field story.

cmd/server/update_cli.go

@@ -2,27 +2,41 @@ package main
 
 import (
 	"context"
+	"cyberstrike-ai/internal/config"
 	"cyberstrike-ai/internal/update"
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 )
 
 // The same one-click update the console page drives, for the two cases a page cannot
 // serve: the process is not running at all, and somebody is ssh'd in with a keyboard.
 // Keeping it in the binary rather than only in a shell script means one implementation of
-// "fetch, fast-forward, rebuild, swap" instead of two that can disagree.
+// "fetch, fast-forward, rebuild, swap" instead of two that can disagree. The update
+// source is read from the same config.yaml field the page saves to, so the keyboard and
+// the button can never update from different repositories.
 func updateCommandIfNeeded(configPath string, check, apply, rollback bool) (bool, int) {
 	if !check && !apply && !rollback {
 		return false, 0
 	}
 	root := filepath.Dir(configPath)
-	opts := update.Options{Root: root}
+	repo, err := config.LoadUpdateRepo(configPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "读取更新源失败: %v\n", err)
+		return true, 1
+	}
+	opts := update.Options{Root: root, Repo: repo}
 	ctx, cancel := context.WithTimeout(context.Background(), 45*time.Minute)
 	defer cancel()
 
+	source := strings.TrimSpace(repo)
+	if source == "" {
+		source = update.DefaultRepoURL + "（官方仓库默认）"
+	}
 	fmt.Printf("安装目录：%s\n", root)
+	fmt.Printf("更新源：%s\n", source)
 	switch {
 	case check:
 		snap, err := update.Check(ctx, opts)
@@ -62,12 +76,16 @@ func printSnapshot(s *update.Snapshot) {
 		fmt.Printf("这个目录不是 git 工作树（%s），无法自动更新\n", s.Root)
 		return
 	}
-	fmt.Printf("分支 %s / 远端 %s / 提交 %s (%s)\n", s.Branch, s.Remote, s.Commit, s.Subject)
+	target := s.TargetBranch
+	if target == "" {
+		target = "?"
+	}
+	fmt.Printf("本机分支 %s / 提交 %s (%s)，更新源默认分支 %s\n", s.Branch, s.Commit, s.Subject, target)
 	if s.CheckError != "" {
 		fmt.Printf("检查失败：%s\n", s.CheckError)
 		return
 	}
-	fmt.Printf("远端最新 %s (%s)，落后 %d 个提交，本地领先 %d 个提交\n", s.RemoteCommit, s.RemoteSubject, s.Behind, s.Ahead)
+	fmt.Printf("更新源最新 %s (%s)，落后 %d 个提交，本地领先 %d 个提交\n", s.RemoteCommit, s.RemoteSubject, s.Behind, s.Ahead)
 	for _, c := range s.Incoming {
 		fmt.Printf("  ○ %s %s\n", c.Commit, c.Subject)
 	}