fix(httpapi): trim whitespace on manually-added account login/password

Pasted app passwords (e.g. mail.ru) often carry a trailing space/newline that
the IMAP server rejects; the CSV path already trims, so make manual add match.
Source and destination passwords remain fully independent (src_pass_enc /
dst_pass_enc), verified end-to-end — this only strips surrounding whitespace.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MMHQTtnQtQqL8muAXHr9kd

internal/httpapi/accounts.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"net/http"
 	"strconv"
+	"strings"
 
 	"github.com/vasyansk/imap-copier/internal/crypto"
 	"github.com/vasyansk/imap-copier/internal/store"
@@ -49,6 +50,12 @@ func (s *Server) handleCreateAccount(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "bad json", http.StatusBadRequest)
 		return
 	}
+	// Trim surrounding whitespace — pasted app passwords / logins often carry a
+	// stray trailing space or newline that the IMAP server rejects.
+	body.SrcLogin = strings.TrimSpace(body.SrcLogin)
+	body.SrcPass = strings.TrimSpace(body.SrcPass)
+	body.DstLogin = strings.TrimSpace(body.DstLogin)
+	body.DstPass = strings.TrimSpace(body.DstPass)
 	srcEnc, err := crypto.Encrypt(s.cfg.EncKey, []byte(body.SrcPass))
 	if err != nil {
 		http.Error(w, "encrypt", http.StatusInternalServerError)