Phase 2a — add 'http' handler (sync forwarder)

The http handler POSTs the Telegram Update JSON to a configurable
internal URL and expects a JSON {text} reply, which it sends back via
sendMessage. Sync : the webhook ack waits for the upstream answer
(timeout default 5s, capped at 30s — Telegram itself closes around 60s).

For slow / unreliable backends use the Phase 3 async handlers once the
queue is in place.

YAML config :

  bots:
    webappbot:
      handler: http
      http:
        url: http://webapp.webapp.svc.cluster.local:8080/telegram/update
        timeout: 5s

Refs ~/.claude/plans/pour-les-notifications-on-inherited-seal.md § Phase 2.

config.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"strings"
+	"time"
 
 	"gopkg.in/yaml.v3"
 )
@@ -18,9 +19,21 @@ type BotConfig struct {
 	// (nil) the registry treats it as true — secure by default. Explicit
 	// `requireAuth: false` is required to expose a bot publicly.
 	// Forced to false for handler=auth (chicken-and-egg).
-	RequireAuth *bool  `yaml:"requireAuth,omitempty"`
-	Token       string `yaml:"-"`
-	Secret      string `yaml:"-"`
+	RequireAuth *bool `yaml:"requireAuth,omitempty"`
+	// HTTP is the per-bot config for the `http` handler. Required when
+	// handler=http. See handler_http.go.
+	HTTP *HTTPConfig `yaml:"http,omitempty"`
+
+	Token  string `yaml:"-"`
+	Secret string `yaml:"-"`
+}
+
+// HTTPConfig drives the `http` handler : the gateway POSTs the Telegram
+// Update JSON to URL, awaits a JSON `{text}` response within Timeout,
+// then sends Text back to the user via sendMessage.
+type HTTPConfig struct {
+	URL     string        `yaml:"url"`
+	Timeout time.Duration `yaml:"timeout,omitempty"`
 }
 
 // LoadConfig reads the YAML routing config and merges per-bot secrets pulled