hub: use Hungarian word passphrases for retrieval passwords

Replace 64-char hex retrieval passwords with 5-word Hungarian
passphrases (e.g. áldás-plazmid-palánta-süvítve-pócgém) for
better UX in disaster recovery scenarios. Embed 29K+ word list
via go:embed. API keys remain hex.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

hub/internal/configgen/passphrase_test.go

@@ -0,0 +1,52 @@
+package configgen
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+)
+
+func TestWordListNoDuplicates(t *testing.T) {
+	seen := make(map[string]bool, len(wordList))
+	for i, w := range wordList {
+		if seen[w] {
+			t.Errorf("duplicate word %q at index %d", w, i)
+		}
+		seen[w] = true
+	}
+	t.Logf("Total unique words: %d", len(seen))
+}
+
+func TestWordListSize(t *testing.T) {
+	if len(wordList) < 10000 {
+		t.Errorf("word list too small: %d (want >= 10000)", len(wordList))
+	}
+	t.Logf("Word list size: %d", len(wordList))
+}
+
+func TestRandomPassphrase(t *testing.T) {
+	p, err := RandomPassphrase(5)
+	if err != nil {
+		t.Fatal(err)
+	}
+	parts := strings.Split(p, "-")
+	if len(parts) != 5 {
+		t.Errorf("expected 5 words, got %d: %s", len(parts), p)
+	}
+	for _, word := range parts {
+		if word == "" {
+			t.Error("empty word in passphrase")
+		}
+	}
+	t.Logf("Sample passphrase: %s", p)
+}
+
+func TestRandomPassphraseSamples(t *testing.T) {
+	for i := 0; i < 5; i++ {
+		p, err := RandomPassphrase(5)
+		if err != nil {
+			t.Fatal(err)
+		}
+		fmt.Printf("  Sample %d: %s\n", i+1, p)
+	}
+}