feat(gitea): support extra outbound HTTP headers via GITEA_EXTRA_HEADERS

Add a GITEA_EXTRA_HEADERS environment variable that accepts a JSON
object of header name/value pairs (e.g. Cloudflare Access
credentials) and applies them to every outbound request to Gitea,
both the raw pkg/gitea.DoJSON/DoBytes path and the SDK-backed
pkg/gitea.NewClient path, without overriding Authorization,
Content-Type, or Accept.

Co-Authored-By: Codet <codet@commitgo.dev> (GPT-5-Codex)

cmd/cmd.go

@@ -2,9 +2,11 @@ package cmd
 
 import (
 	"context"
+	"encoding/json"
 	"flag"
 	"fmt"
 	"io"
+	"net/http"
 	"os"
 	"strconv"
 	"strings"
@@ -86,6 +88,7 @@ func initFlagSet(fs *flag.FlagSet, args []string, getenv func(string) string, re
 		fmt.Fprintf(w, "  GITEA_ACCESS_TOKEN\tProvide access token\n")
 		fmt.Fprintf(w, "  GITEA_ACCESS_TOKEN_FILE\tPath to a file containing the access token (e.g. a Docker secret)\n")
 		fmt.Fprintf(w, "  GITEA_DEBUG\tSet to 'true' for debug mode\n")
+		fmt.Fprintf(w, "  GITEA_EXTRA_HEADERS\tJSON object of extra HTTP headers to send with Gitea API requests\n")
 		fmt.Fprintf(w, "  GITEA_HOST\tOverride Gitea host URL\n")
 		fmt.Fprintf(w, "  GITEA_INSECURE\tSet to 'true' to ignore TLS errors\n")
 		fmt.Fprintf(w, "  GITEA_MAX_INLINE_ATTACHMENT_BYTES\tOverride inline image attachment size limit in bytes\n")
@@ -164,6 +167,18 @@ func initFlagSet(fs *flag.FlagSet, args []string, getenv func(string) string, re
 			flagPkg.MaxInlineAttachmentBytes = parsed
 		}
 	}
+	if val := getenv("GITEA_EXTRA_HEADERS"); val != "" {
+		var headers map[string]string
+		if err := json.Unmarshal([]byte(val), &headers); err != nil {
+			fmt.Fprintf(stderr, "invalid GITEA_EXTRA_HEADERS: %v\n", err)
+			osExit(1)
+		}
+		extraHeaders := make(http.Header, len(headers))
+		for name, value := range headers {
+			extraHeaders.Set(name, value)
+		}
+		flagPkg.ExtraHeaders = extraHeaders
+	}
 }
 
 // normalizeScope trims whitespace, lowercases, and converts internal spaces