fix(tts): wire dashboard tts.timeout_ms through ApplySystemConfigs + seed

ApplySystemConfigs and seedConfigForContext both handle tts.provider,
tts.auto, tts.mode, tts.max_length — but neither carries tts.timeout_ms.
Result: the dashboard /tts page Timeout (ms) input is inert; cfg.Tts.TimeoutMs
stays at config.json default; setupTTS passes 0 to provider constructors;
each provider falls back to its hardcoded default (e.g. edge = 30s).

Two-line fix to mirror the existing pattern for the other tts.* keys.

cmd/gateway_system_config_sync.go

@@ -121,6 +121,7 @@ func seedConfigForContext(ctx context.Context, sc store.SystemConfigStore, cfg *
 	set("tts.auto", cfg.Tts.Auto)
 	set("tts.mode", cfg.Tts.Mode)
 	setInt("tts.max_length", cfg.Tts.MaxLength)
+	setInt("tts.timeout_ms", cfg.Tts.TimeoutMs)
 
 	// Cron
 	setInt("cron.max_retries", cfg.Cron.MaxRetries)

internal/config/config_system.go

@@ -67,6 +67,7 @@ func (c *Config) ApplySystemConfigs(configs map[string]string) {
 	str("tts.auto", &c.Tts.Auto)
 	str("tts.mode", &c.Tts.Mode)
 	integer("tts.max_length", &c.Tts.MaxLength)
+	integer("tts.timeout_ms", &c.Tts.TimeoutMs)
 
 	// Cron
 	integer("cron.max_retries", &c.Cron.MaxRetries)