docs(timeline): register timeline domain in package tables and diagrams

Add timeline/ to the root and backend package tables, TimelineEvent to the
domain-model entity tables, TimelineEvent/EventType/Zeitstrahl to the
glossary, a new l3-backend-timeline C4 component diagram, and the
timeline_events table + two join tables (with their CHECKs and cascade FKs)
to the db-orm and db-relationships ER diagrams. Bumps the db-orm snapshot to
V77.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/CLAUDE.md

@@ -42,6 +42,7 @@ src/main/java/org/raddatz/familienarchiv/
 │   └── relationship/    # PersonRelationship sub-domain
 ├── security/            # SecurityConfig, Permission, @RequirePermission, PermissionAspect
 ├── tag/                 # Tag domain — Tag, TagService, TagController
+├── timeline/            # Timeline (Zeitstrahl) domain — TimelineEvent, EventType, TimelineEventRepository
 └── user/                # User domain — AppUser, UserGroup, UserService
 ```
 
@@ -67,6 +68,7 @@ For per-domain ownership and public surface, see each domain's `README.md`.
 | `Comment`                   | `document_comments`             | Threaded comments with mentions                                                 |
 | `Notification`              | `notifications`                 | User notification feed                                                          |
 | `OcrJob` / `OcrJobDocument` | `ocr_jobs`, `ocr_job_documents` | Batch OCR job tracking                                                          |
+| `TimelineEvent`             | `timeline_events`               | Curated Zeitstrahl event; ManyToMany persons + documents (join FKs ON DELETE CASCADE); `@Version` + NOT NULL createdBy/updatedBy |
 
 **`DocumentStatus` lifecycle:** `PLACEHOLDER → UPLOADED → TRANSCRIBED → REVIEWED → ARCHIVED`