Initial commit: FunStat MCP Server Go implementation

- Telegram integration for customer statistics
- MCP server implementation with rate limiting
- Cache system for performance optimization
- Multi-language support
- RESTful API endpoints

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

internal/cache/cache.go

@@ -0,0 +1,70 @@
+package cache
+
+import (
+	"sync"
+	"time"
+)
+
+type entry struct {
+	value   string
+	expires time.Time
+}
+
+type Cache struct {
+	ttl    time.Duration
+	mu     sync.RWMutex
+	values map[string]entry
+}
+
+func New(ttl time.Duration) *Cache {
+	if ttl <= 0 {
+		ttl = time.Hour
+	}
+	return &Cache{
+		ttl:    ttl,
+		values: make(map[string]entry),
+	}
+}
+
+func (c *Cache) Get(key string) (string, bool) {
+	c.mu.RLock()
+	e, ok := c.values[key]
+	c.mu.RUnlock()
+	if !ok {
+		return "", false
+	}
+	if time.Now().After(e.expires) {
+		c.mu.Lock()
+		delete(c.values, key)
+		c.mu.Unlock()
+		return "", false
+	}
+	return e.value, true
+}
+
+func (c *Cache) Set(key string, value string) {
+	c.mu.Lock()
+	c.values[key] = entry{
+		value:   value,
+		expires: time.Now().Add(c.ttl),
+	}
+	c.mu.Unlock()
+}
+
+func (c *Cache) ClearExpired() int {
+	now := time.Now()
+	c.mu.Lock()
+	removed := 0
+	for k, v := range c.values {
+		if now.After(v.expires) {
+			delete(c.values, k)
+			removed++
+		}
+	}
+	c.mu.Unlock()
+	return removed
+}
+
+func (c *Cache) TTL() time.Duration {
+	return c.ttl
+}