Initial release of go-telegram

A fully-generated, strongly-typed Go client for the Telegram Bot API.

* 176 methods + 301 types generated from Bot API v10.0
* 1408 auto-generated tests (8 scenarios per method)
* Typed unions throughout — no 'any' in the public surface
* Pluggable HTTP transport and JSON codec (default goccy/go-json)
* Built-in retry middleware honouring Telegram's retry_after
* Generic dispatcher with filters and conversation handlers
* Self-verifying codegen pipeline (regen → audit → emit → run tests)
* 14 example bots covering common patterns

transport/backoff.go

@@ -0,0 +1,51 @@
+package transport
+
+import (
+	"math"
+	"math/rand/v2"
+	"time"
+)
+
+// BackoffStrategy returns the duration to wait before the next attempt
+// after `attempt` consecutive failures (1-based). Implementations must
+// be safe to call from a single goroutine.
+type BackoffStrategy interface {
+	NextDelay(attempt int) time.Duration
+}
+
+// ExponentialBackoff implements capped exponential back-off with jitter.
+// Defaults: Base=500ms, Max=30s, Factor=2.0, Jitter=0.2.
+type ExponentialBackoff struct {
+	Base   time.Duration
+	Max    time.Duration
+	Factor float64
+	Jitter float64 // 0..1; fraction of computed delay added/subtracted at random
+}
+
+// DefaultBackoff returns an ExponentialBackoff with library defaults.
+func DefaultBackoff() *ExponentialBackoff {
+	return &ExponentialBackoff{
+		Base:   500 * time.Millisecond,
+		Max:    30 * time.Second,
+		Factor: 2.0,
+		Jitter: 0.2,
+	}
+}
+
+// NextDelay implements BackoffStrategy.
+func (b *ExponentialBackoff) NextDelay(attempt int) time.Duration {
+	if attempt < 1 {
+		attempt = 1
+	}
+	d := float64(b.Base) * math.Pow(b.Factor, float64(attempt-1))
+	if b.Jitter > 0 {
+		d *= 1 + (rand.Float64()*2-1)*b.Jitter
+	}
+	if d > float64(b.Max) {
+		d = float64(b.Max)
+	}
+	if d < 0 {
+		d = 0
+	}
+	return time.Duration(d)
+}