homelab: add tf verbs + stack/git-crypt substrate

Adds the tf verb-group and the resolver substrate beneath it, continuing the
v0.1 infra-loop build.

- substrate: findInfraRoot (walk up to terragrunt.hcl + stacks/), stack→dir
  resolver, and repo/remote/git-crypt detection (preferRemote forgejo>origin,
  hasGitCryptAttr, gitCryptFlags) — the last is for `work` next.
- tf plan/validate/fmt/force-unlock/apply, resolving the stack from cwd and
  delegating to scripts/tg (which owns state decrypt/encrypt, the Vault lock,
  and the ingress auth-comment check) rather than calling terragrunt directly.
- tf apply is presence-coupled: claims stack:<name>, ALWAYS releases on exit
  (normal, error, or SIGINT/SIGTERM via sync.Once + signal handler) — fixing
  the documented ~200-claim leak — and prints an out-of-band reminder since CI
  applies canonically on push.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

cli/repo.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"os/exec"
+	"strings"
+)
+
+// preferRemote picks the canonical remote: forgejo if present, else origin,
+// else the first listed. (For infra, origin and forgejo both point at Forgejo.)
+func preferRemote(remotes []string) string {
+	has := map[string]bool{}
+	for _, r := range remotes {
+		has[r] = true
+	}
+	switch {
+	case has["forgejo"]:
+		return "forgejo"
+	case has["origin"]:
+		return "origin"
+	case len(remotes) > 0:
+		return remotes[0]
+	default:
+		return ""
+	}
+}
+
+// hasGitCryptAttr reports whether .gitattributes content enables git-crypt.
+func hasGitCryptAttr(gitattributes string) bool {
+	return strings.Contains(gitattributes, "filter=git-crypt")
+}
+
+// gitCryptFlags are the per-command flags that disable smudge/clean so git
+// operations in a git-crypt repo don't try to decrypt (NEVER persisted to config).
+func gitCryptFlags() []string {
+	return []string{
+		"-c", "filter.git-crypt.smudge=cat",
+		"-c", "filter.git-crypt.clean=cat",
+		"-c", "filter.git-crypt.required=false",
+	}
+}
+
+// gitOutput runs `git -C dir <args>` and returns trimmed stdout.
+func gitOutput(dir string, args ...string) (string, error) {
+	cmd := exec.Command("git", append([]string{"-C", dir}, args...)...)
+	out, err := cmd.Output()
+	return strings.TrimSpace(string(out)), err
+}
+
+func gitRepoRoot(dir string) (string, error) {
+	return gitOutput(dir, "rev-parse", "--show-toplevel")
+}
+
+// gitRemotes lists configured remote names for the repo at dir.
+func gitRemotes(dir string) ([]string, error) {
+	out, err := gitOutput(dir, "remote")
+	if err != nil {
+		return nil, err
+	}
+	if out == "" {
+		return nil, nil
+	}
+	return strings.Split(out, "\n"), nil
+}