chore: remove hand-rolled telemetry pkg; ignore build binaries

- delete internal/telemetry (replaced by oss-telemetry library in prev commit)
- gitignore root /mcp and /worker build artifacts

internal/telemetry/telemetry.go

@@ -1,55 +0,0 @@
-// Package telemetry sends anonymous OSS usage pings.
-package telemetry
-
-import (
-	"bytes"
-	"context"
-	"encoding/json"
-	"net/http"
-	"strings"
-	"time"
-
-	"github.com/rs/zerolog/log"
-)
-
-const endpoint = "https://oss.raczylo.com/v1/ping"
-
-type pingPayload struct {
-	Project string `json:"project"`
-	Version string `json:"version"`
-	Ts      int64  `json:"ts"`
-}
-
-// Ping fires an anonymous analytics ping asynchronously. Never blocks the caller.
-// Silently skips dev/dirty builds; all errors are logged at debug level only.
-func Ping(project, version string) {
-	if version == "dev" || strings.Contains(version, "dirty") {
-		return
-	}
-	go func() {
-		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
-		defer cancel()
-
-		body, err := json.Marshal(pingPayload{
-			Project: project,
-			Version: strings.TrimPrefix(version, "v"),
-			Ts:      time.Now().Unix(),
-		})
-		if err != nil {
-			return
-		}
-
-		req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewReader(body))
-		if err != nil {
-			return
-		}
-		req.Header.Set("Content-Type", "application/json")
-
-		resp, err := http.DefaultClient.Do(req)
-		if err != nil {
-			log.Debug().Err(err).Msg("telemetry ping failed")
-			return
-		}
-		resp.Body.Close()
-	}()
-}