feat: draft mode, admin branding, and workflow improvements

Draft Mode:
- Events are created as drafts by default — no email sent until published
- Add "Publish & Notify Client" button with confirmation dialog
- Draft banner with yellow styling on event details page
- Draft filter tab in events list
- Gallery middleware blocks public access to draft events
- Migration 076 adds is_draft column to events table

Admin Draft Preview:
- Admins can preview draft galleries via JWT preview token (?preview=)
- "View Gallery" link on drafts auto-appends preview token

Admin & Login Page Branding:
- Admin header uses configured company logo/name from branding settings
- Login page shows configured logo instead of hardcoded PicPeak
- Respects logo_display_mode (logo_only, text_only, logo_and_text)

OG Tag Branding:
- DynamicFavicon component updates OG meta tags and page title from
  branding settings

Editable Client Email:
- Customer email is now editable after event creation in edit mode

Branding Inheritance:
- New events inherit hero logo settings (visibility, size, position)
  from global branding configuration

Share Link Full Domain URL:
- New getFrontendBaseUrl() utility with DB fallback to general_site_url
- Used in email processor and share link service

backend/src/services/shareLinkService.js

@@ -1,6 +1,7 @@
 const { db } = require('../database/db');
 const { formatBoolean } = require('../utils/dbCompat');
 const { extractShareToken, isPotentialShareToken, buildSharePath } = require('../utils/shareLinkUtils');
+const { getFrontendBaseUrl } = require('../utils/frontendUrl');
 
 const SETTING_KEY = 'general_short_gallery_urls';
 const CACHE_TTL_MS = 60_000;
@@ -87,7 +88,7 @@ const buildShareLinkVariants = async ({ slug, shareToken }) => {
 
   const shortEnabled = await isShortGalleryUrlsEnabled();
   const sharePath = buildSharePath(slug, shareToken, shortEnabled);
-  const frontendBase = (process.env.FRONTEND_URL || '').replace(/\/$/, '');
+  const frontendBase = await getFrontendBaseUrl();
   const shareUrl = frontendBase ? `${frontendBase}${sharePath}` : sharePath;
 
   return {
@@ -112,7 +113,8 @@ const getEventShareToken = (event) => {
 
 const ACTIVE_EVENT_FILTER = {
   is_active: formatBoolean(true),
-  is_archived: formatBoolean(false)
+  is_archived: formatBoolean(false),
+  is_draft: formatBoolean(false)
 };
 
 const resolveShareIdentifier = async (identifier) => {