Fix security and correctness issues found in full-codebase audit

- Restrict meetingPassword field so it isn't leaked via the public REST/GraphQL API
- Fix booking slot computation to use Europe/Berlin time instead of the server's UTC clock
- Reset email verification when a customer changes their email address
- Fix ICS calendar injection via unescaped carriage returns in event descriptions
- Bind WebRTC meeting kicks to a persistent client id so they survive a rejoin
- Move the meeting signaling token out of the WebSocket query string into the first message
- Prevent duplicate signaling connections from leaking when the same participant reconnects
- Use the rightmost X-Forwarded-For entry for rate limiting (single trusted reverse proxy)
- Use constant-time comparison for the cron endpoint's bearer token
- Remove SVG from allowed Media upload types (stored-XSS risk, unused anyway)
- Add baseline security headers and a CSP to next.config.ts
- Fix CI/CD script injection via unsanitized git ref names in release.yml

lib/calendar/ics.ts

@@ -15,6 +15,11 @@ function escapeICSText(value: string): string {
     .replace(/\\/g, "\\\\")
     .replace(/;/g, "\\;")
     .replace(/,/g, "\\,")
+    // \r must be stripped (not just \n escaped): many ICS parsers split
+    // lines on a bare CR too, so leaving it unescaped lets untrusted text
+    // (e.g. a customer's booking message ending up in DESCRIPTION) break
+    // out of the property value and inject extra iCalendar lines/properties.
+    .replace(/\r\n?/g, "\\n")
     .replace(/\n/g, "\\n");
 }