feat(base): themed DatePicker + TimePicker for activity forms

Scaffolds shadcn-vue Calendar + adds @internationalized/date, then
wraps them in two small shared components living alongside ImageUpload
for reuse across activity / market / future forms.

DatePicker — Popover + Calendar, bridges the wire format (YYYY-MM-DD
string) to reka-ui's CalendarDate. Closes on pick (the Calendar
primitive doesn't auto-close). Optional min-date for forward-only
selection.

TimePicker — two shadcn <Select> dropdowns (HH 00–23, MM at minuteStep
granularity, default 15). Bound to a single "HH:MM" string externally,
clearable. Mobile-first: a tap opens the native sheet / wheel — no
typeahead overlay (reka-ui's Select doesn't expose typeahead on the
closed trigger and the workaround proved brittle against its internal
document-level key handling).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -43,6 +43,7 @@
     "make": "electron-forge make"
   },
   "dependencies": {
+    "@internationalized/date": "^3.12.1",
     "@tanstack/vue-table": "^8.21.3",
     "@vee-validate/zod": "^4.15.1",
     "@vueuse/components": "^12.5.0",
@@ -63,7 +64,7 @@
     "qr-scanner": "^1.4.2",
     "qrcode": "^1.5.4",
     "radix-vue": "^1.9.13",
-    "reka-ui": "^2.6.0",
+    "reka-ui": "^2.9.7",
     "tailwind-merge": "^2.6.0",
     "tailwindcss-animate": "^1.0.7",
     "unique-names-generator": "^4.7.1",