feat: add governed Calendar DSAR coverage

docs/CALENDAR_INTEGRATION_CONCEPT.md

@@ -191,6 +191,35 @@ the same tenant scope.
 
 ## Integration Points
 
+## Data-subject requests and retention boundaries
+
+Calendar implements the optional `privacy.dsar.calendar` capability used by
+Core's governed data-subject-request workflow. A search is bounded to the
+effective tenant and matches normalized organizer or attendee email, direct
+membership references, and independently corroborated namespaced Calendar
+collection or event references. Only the matching party fragment is projected;
+unrelated attendees and unrelated events in the same collection are not copied
+into the case.
+
+The projection includes safe event and collection context, personal view
+preferences, subject-owned synchronization configuration, outbox outcomes, and
+migration state. It never includes raw ICS or complete iCalendar objects,
+collection URLs, remote resource hrefs or ETags, sync tokens, usernames,
+credential references or ciphertext, idempotency keys, worker leases, provider
+error text, or opaque metadata. An authorized reviewer must use Calendar's own
+screens when excluded content is necessary to decide the request.
+
+Synchronized, correlated, deleted, queued, and migrated state is classified as
+retained evidence with an explicit reason. Local collections and events and
+active credential metadata remain manual-review items because erasure can
+affect recurrence, other attendees, institutional scheduling, remote systems,
+and retention duties. The only executable provider action is deletion of the
+subject's personal view preference; execution locks and revalidates its tenant
+and owner and is idempotent. Event, attendee, credential, outbox, and migration
+records are never mutated directly by the DSAR provider. Related meeting-poll,
+mail, and delivery data remains owned by Scheduling, Poll, Mail, and their own
+providers.
+
 ### Scheduling
 
 `govoplan-scheduling` should use calendar for: