feat: add Cloudflare AI TTS engine (aura-2-en) with voice grouping in UI

backend/cmd/backend/main.go

@@ -26,6 +26,7 @@ import (
 	"github.com/hibiken/asynq"
 	"github.com/libnovel/backend/internal/asynqqueue"
 	"github.com/libnovel/backend/internal/backend"
+	"github.com/libnovel/backend/internal/cfai"
 	"github.com/libnovel/backend/internal/config"
 	"github.com/libnovel/backend/internal/kokoro"
 	"github.com/libnovel/backend/internal/meili"
@@ -114,6 +115,15 @@ func run() error {
 		log.Info("POCKET_TTS_URL not set — pocket-tts voices unavailable in backend")
 	}
 
+	// ── Cloudflare Workers AI (voice sample generation + audio-stream live TTS) ──
+	var cfaiClient cfai.Client
+	if cfg.CFAI.AccountID != "" && cfg.CFAI.APIToken != "" {
+		cfaiClient = cfai.New(cfg.CFAI.AccountID, cfg.CFAI.APIToken, cfg.CFAI.Model)
+		log.Info("cloudflare AI TTS enabled", "model", cfg.CFAI.Model)
+	} else {
+		log.Info("CFAI_ACCOUNT_ID/CFAI_API_TOKEN not set — CF AI voices unavailable in backend")
+	}
+
 	// ── Meilisearch (search reads only; indexing is the runner's job) ────────
 	var searchIndex meili.Client
 	if cfg.Meilisearch.URL != "" {
@@ -163,6 +173,7 @@ func run() error {
 			SearchIndex:      searchIndex,
 			Kokoro:           kokoroClient,
 			PocketTTS:        pocketTTSClient,
+			CFAI:             cfaiClient,
 			Log:              log,
 		},
 	)