feat(local_backend): reservations, print analytics, workday summary, zone-PIN management

- New reservations module: model, schema, router (CRUD + status updates + upcoming alerts)
  and background task for auto-expiring stale reservations
- Reports: print_products, print_categories, print_tables analytics endpoints
  plus meta_products and business_day_summary for workday close/view flow
- printer_service: configurable font sizes/weights, donut/bar chart print layout helpers,
  analytics print blocks per printer
- tables/schemas: surfaced color, zone, and other new fields on Table, Product, User, Printer
- demo_seed.py for quick dev DB population; wipe_database.py utility

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

local_backend/routers/settings.py

@@ -27,6 +27,7 @@ VALID_SETTINGS = {
     # Print layout
     "print.ticket_mode":       "Kitchen ticket layout mode: 'detailed' or 'compact'",
     "print.divider_style":     "Divider character used between sections: dash, equals, star, or empty",
+    "print.dot_style":         "Dot-leader style for item lines: STYLE:SIZE:BOLD where STYLE is dot_space|dot|dash_space|underscore, SIZE is ESC ! base byte (0/16/32/48), BOLD 0|1",
     # Print font settings — values are "SIZE:BOLD:CAPS" where SIZE is ESC ! base byte (0/16/32/48), BOLD 0|1, CAPS 0|1
     "print.font_order_number": "Font for order number header: SIZE:BOLD:CAPS",
     "print.font_meta":         "Font for table/waiter/time header block: SIZE:BOLD:CAPS",
@@ -53,10 +54,11 @@ DEFAULTS = {
     "shifts.waiter_self_end": "true",
     "business_day.force_close_allowed": "true",
     "system.timezone": "Europe/Athens",
-    "ui.table_colours": "",
+    "ui.table_colours": '{"light":{"free":{"cardBg":"#dde5ef","badgeBg":"rgba(255,255,255,0.92)","nameText":"#3d5270","badgeText":"#3d5270"},"mine":{"cardBg":"#e8610a","badgeBg":"rgba(255,255,255,0.92)","nameText":"#ffffff","badgeText":"#e8610a"},"open":{"cardBg":"#FF8F60","badgeBg":"rgba(255,255,255,0.92)","nameText":"#ffffff","badgeText":"#FF8F60"},"partially_paid":{"cardBg":"#FFDC67","badgeBg":"rgba(255,255,255,0.92)","nameText":"#ffffff","badgeText":"#d4a800"},"paid":{"cardBg":"#81D264","badgeBg":"rgba(255,255,255,0.92)","nameText":"#ffffff","badgeText":"#81D264"}},"dark":{"free":{"cardBg":"#243044","badgeBg":"rgba(255,255,255,0.92)","nameText":"#94b8d4","badgeText":"#94b8d4"},"mine":{"cardBg":"#e8610a","badgeBg":"rgba(255,255,255,0.92)","nameText":"#ffffff","badgeText":"#e8610a"},"open":{"cardBg":"#FF8F60","badgeBg":"rgba(255,255,255,0.92)","nameText":"#ffffff","badgeText":"#FF8F60"},"partially_paid":{"cardBg":"#FFDC67","badgeBg":"rgba(255,255,255,0.92)","nameText":"#ffffff","badgeText":"#d4a800"},"paid":{"cardBg":"#81D264","badgeBg":"rgba(255,255,255,0.92)","nameText":"#ffffff","badgeText":"#81D264"}}}',
     "dev.spoof_printing": "false",
     "print.ticket_mode":       "detailed",
     "print.divider_style":     "dash",
+    "print.dot_style":         "dot_space:0:0",
     "print.font_order_number": "48:1:0",
     "print.font_meta":         "0:0:0",
     "print.font_item_name":    "16:1:0",