Prevent scheduling events in the past + full events-section audit

Audited the whole events flow end-to-end (create, hosting dashboard, discovery
grid, detail, RSVP, sponsors) and confirmed the wiring is coherent:
- Create → parse → display round-trips correctly for sponsors, tour/spot/crew/
  musician links, entry fee, and featured listings
- Sponsor parser safely skips shop-coordinate `sponsor` tags (no name at pos 2),
  so events and tour/shop sponsorships never collide
- Batch RSVP counts feed the grid; hosting dashboard + detail keep per-item counts

Fix surfaced by the audit: CreateEventPage let a host pick a start time in the
past, silently producing a dead event in the Past tab. Added a `min={today}` on
the date pickers and a submit guard (10-min grace) with a clear message.

Co-authored-by: shakespeare.diy <assistant@shakespeare.diy>

src/pages/CreateEventPage.tsx

@@ -1,4 +1,4 @@
-import { useState, useEffect } from 'react';
+import { useState, useEffect, useMemo } from 'react';
 import { useSeoMeta } from '@unhead/react';
 import { useNavigate, useSearchParams } from 'react-router-dom';
 import ngeohash from 'ngeohash';
@@ -158,6 +158,14 @@ export default function CreateEventPage() {
     return acc;
   }, {} as Record<string, SkateSpot[]>);
 
+  // Today (local) as YYYY-MM-DD, used as the min for the date pickers so hosts
+  // can't accidentally schedule an event in the past.
+  const todayStr = useMemo(() => {
+    const d = new Date();
+    const off = d.getTimezoneOffset();
+    return new Date(d.getTime() - off * 60_000).toISOString().split('T')[0];
+  }, []);
+
   const toggleType = (type: string) => {
     setSelectedTypes((prev) =>
       prev.includes(type) ? prev.filter((t) => t !== type) : [...prev, type]
@@ -272,6 +280,17 @@ export default function CreateEventPage() {
       return;
     }
 
+    // Guard against scheduling in the past (a 10-min grace window covers
+    // "starting right now" without rejecting it).
+    if (startTimestamp < Math.floor(Date.now() / 1000) - 600) {
+      toast({
+        title: 'That start time is in the past',
+        description: 'Pick a date and time in the future so skaters can RSVP and show up.',
+        variant: 'destructive',
+      });
+      return;
+    }
+
     // Parse end time if provided
     let endTimestamp: number | undefined;
     if (endDate && endTime) {
@@ -535,6 +554,7 @@ export default function CreateEventPage() {
                   <Input
                     type="date"
                     value={startDate}
+                    min={todayStr}
                     onChange={(e) => setStartDate(e.target.value)}
                     required
                   />
@@ -554,6 +574,7 @@ export default function CreateEventPage() {
                   <Input
                     type="date"
                     value={endDate}
+                    min={startDate || todayStr}
                     onChange={(e) => setEndDate(e.target.value)}
                   />
                   <Input