config: add TTLOverrides to CacheConfig

internal/config/config.go

@@ -63,10 +63,11 @@ type StackOverflowConfig struct {
 
 // CacheConfig holds Valkey/Redis cache settings.
 type CacheConfig struct {
-	Address    string `toml:"address"`     // Valkey server address (e.g. "localhost:6379")
+	Address      string            `toml:"address"`       // Valkey server address (e.g. "localhost:6379")
-	Password   string `toml:"password"`    // Auth password (empty = none)
+	Password     string            `toml:"password"`      // Auth password (empty = none)
-	DB         int    `toml:"db"`          // Database index (default 0)
+	DB           int               `toml:"db"`            // Database index (default 0)
-	DefaultTTL string `toml:"default_ttl"` // Cache TTL (e.g. "5m", default "5m")
+	DefaultTTL   string            `toml:"default_ttl"`   // Cache TTL (e.g. "5m", default "5m")
+	TTLOverrides map[string]string `toml:"ttl_overrides"` // engine -> duration string
 }
 
 // CORSConfig holds CORS middleware settings.
@@ -284,6 +285,20 @@ func (c *Config) CacheTTL() time.Duration {
 	return 5 * time.Minute
 }
 
+// CacheTTLOverrides returns parsed TTL overrides from config.
+func (c *Config) CacheTTLOverrides() map[string]time.Duration {
+	if len(c.Cache.TTLOverrides) == 0 {
+		return nil
+	}
+	out := make(map[string]time.Duration, len(c.Cache.TTLOverrides))
+	for engine, durStr := range c.Cache.TTLOverrides {
+		if d, err := time.ParseDuration(durStr); err == nil && d > 0 {
+			out[engine] = d
+		}
+	}
+	return out
+}
+
 // RateLimitWindow parses the rate limit window into a time.Duration.
 func (c *Config) RateLimitWindow() time.Duration {
 	if d, err := time.ParseDuration(c.RateLimit.Window); err == nil && d > 0 {