feat: add three-level logging with per-request debug output

- New --log-level flag: debug (default info), info, silent
  debug: every API request logged (method, URL, status, duration)
  info:  normal events (batch progress, entry counts, summaries)
  silent: only warnings and fatal errors
- Replaced all log.Printf/Fatalf calls with level-gated helpers
- API request timing added to queryWikiArticle, queryWikidataBatch, downloadFile
- Retries and backoff logged in debug mode

1 files changed, 5 insertions, 2 deletions

diff --git a/src/wikiarticle.go b/src/wikiarticle.go
index c1ce486..5f7aaa1 100644
--- a/src/wikiarticle.go
+++ b/src/wikiarticle.go
@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"log"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -39,10 +38,11 @@ func (a *App) queryWikiArticle(name string) (wikiArticleEntry, int, error) {
 
 	var resp *http.Response
 	var err error
+	start := time.Now()
 	for attempt := 0; attempt < 5; attempt++ {
 		if attempt > 0 {
 			backoff := 1 << attempt
-			log.Printf("retry %d/%d for %s after %ds backoff", attempt, 4, name, backoff)
+			logHTTPRetry(attempt, 4, backoff, name)
 			time.Sleep(time.Duration(backoff) * time.Second)
 		}
 
@@ -59,15 +59,18 @@ func (a *App) queryWikiArticle(name string) (wikiArticleEntry, int, error) {
 		if resp.StatusCode != http.StatusOK {
 			body, _ := io.ReadAll(io.LimitReader(resp.Body, 2048))
 			resp.Body.Close()
+			logHTTPRequest("GET", reqURL, resp.StatusCode, time.Since(start).Seconds())
 			return wikiArticleEntry{}, resp.StatusCode, fmt.Errorf("HTTP %d: %s", resp.StatusCode, body)
 		}
 
 		break
 	}
 	if err != nil {
+		logHTTPRequest("GET", reqURL, 0, time.Since(start).Seconds())
 		return wikiArticleEntry{}, 0, fmt.Errorf("http get: %w", err)
 	}
 	defer resp.Body.Close()
+	logHTTPRequest("GET", reqURL, resp.StatusCode, time.Since(start).Seconds())
 
 	var articles []map[string]interface{}
 	if err := json.NewDecoder(resp.Body).Decode(&articles); err != nil {