#280: remove PALETTE_TRUSTED_IP_HEADER, key rate limits on peer address only

Owner follow-up to the #280 fix (PR #284): the trusted-header env var is
gone. clientIP() now uses the peer address exclusively and ignores all
client-supplied IP headers; the env var row is removed from the README.

internal/api/server.go

@@ -28,10 +28,6 @@ type Config struct {
 	DBPath       string
 	MaxTextBytes int64
 	MaxItemBytes int64
-	// TrustedIPHeader optionally names a proxy-controlled client-IP header
-	// (e.g. CF-Connecting-IP behind Cloudflare) to key rate limits on. Empty
-	// (default) keys on the peer address only. See clientip.go (#280).
-	TrustedIPHeader string
 }
 
 type apiServer struct {
@@ -43,7 +39,6 @@ type apiServer struct {
 }
 
 func NewServer(st *store.Store, cfg Config, ui *web.UI, ss *settingsStore, adminKey string) *apiServer {
-	SetTrustedIPHeader(cfg.TrustedIPHeader) // #280
 	return &apiServer{store: st, cfg: cfg, ui: ui, settings: ss, adminKey: adminKey}
 }