feat: org-scoped appointments backend, wire appointments page

Add the appointments table, validation, service and CRUD routes
(/api/appointments, RBAC-gated) and the matching frontend data module.
The appointments page now loads and persists real data; KPIs are computed
from it and the schedule/calendar anchor to the real current date.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/drizzle/meta/_journal.json

@@ -15,6 +15,13 @@
       "when": 1780591375930,
       "tag": "0001_boring_puck",
       "breakpoints": true
+    },
+    {
+      "idx": 2,
+      "version": "7",
+      "when": 1780849813505,
+      "tag": "0002_fluffy_longshot",
+      "breakpoints": true
     }
   ]
 }