Fix CalDAV/CardDAV multiget loading entire collections into memory

A REPORT multiget for a handful of resources previously listed the
whole calendar/address book (every row incl. ical_data/vcard) and
filtered by href in Rust with an O(N×M) substring scan. Large
collections paid full-table latency, RAM and DB CPU on every sync.

- Add find_events_by_ical_uids / get_contacts_by_uids through every
  layer (domain repo trait → PG repo → storage port/adapter → use case
  → handler) using one indexed `= ANY($2)` query, mirroring the
  existing single-UID lookups.
- Extract UIDs from multiget hrefs with a shared, tested
  uid_from_multiget_href helper (percent-decoding, case-insensitive
  extension strip, collection hrefs rejected). Exact UID matching also
  removes the false positives the old substring filter allowed.
- CalDAV PROPFIND single-event path now uses the existing indexed
  get_event_by_ical_uid instead of listing all events.
- Honour the already-documented limit/offset query params on
  GET /api/address-books/{id}/contacts: optional ListQuery fields
  thread through ContactUseCase::list_contacts to a paginated repo
  query. Omitted params keep returning the full book (frontend and
  DAV listing/sync paths unchanged).

https://claude.ai/code/session_0193Hff42gaA962wThxMGSd1

src/domain/repositories/calendar_event_repository.rs

@@ -53,6 +53,16 @@ pub trait CalendarEventRepository: Send + Sync + 'static {
         ical_uid: &str,
     ) -> CalendarEventRepositoryResult<Option<CalendarEvent>>;
 
+    /// Finds the events matching any of the given iCalendar UIDs in one
+    /// indexed query (`ical_uid = ANY(...)`). Used by CalDAV multiget so a
+    /// request for a handful of events never pays for the whole calendar.
+    /// UIDs with no matching event are silently absent from the result.
+    async fn find_events_by_ical_uids(
+        &self,
+        calendar_id: &Uuid,
+        ical_uids: &[String],
+    ) -> CalendarEventRepositoryResult<Vec<CalendarEvent>>;
+
     /// Counts events in a calendar
     async fn count_events_in_calendar(
         &self,