enhance(runner): add extra HTTP headers (#1269)

Add `runner.extra_headers` for reverse proxies that require request headers on the runner's API requests to Gitea, like registration, polling and log and status reports.

Headers the runner sets itself (authentication, User-Agent, protocol headers) stay authoritative. Extra headers are dropped when a redirect changes the hostname or leaves HTTPS, while the runner's own authentication headers follow redirects as before. Invalid or case-insensitively duplicated header names are rejected at config load.

Fixes: https://gitea.com/gitea/runner/issues/171
Co-authored-by: silverwind <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1269
Co-authored-by: bircni <[email protected]>

internal/app/cmd/daemon.go

@@ -174,6 +174,7 @@ func runDaemon(ctx context.Context, daemArgs *daemonArgs, configFile *string) fu
 			reg.UUID,
 			reg.Token,
 			config.RequestTimeout,
+			cfg.Runner.ExtraHeaders,
 		)
 
 		runner := run.NewRunner(cfg, reg, cli)

internal/app/cmd/register.go

@@ -367,6 +367,7 @@ func doRegister(ctx context.Context, cfg *config.Config, inputs *registerInputs)
 		"",
 		"",
 		config.RequestTimeout,
+		cfg.Runner.ExtraHeaders,
 	)
 
 	if _, err := cli.Ping(ctx, connect.NewRequest(&pingv1.PingRequest{