docs(timeline): RTM, CLAUDE.md, and C4 updates for #777 assembly endpoint

- Add 20 REQ-NNN rows for issue #777 (all Done) to .specify/rtm.md
- Update CLAUDE.md timeline package description with TimelineService/TimelineController
- Extend l3-backend-timeline.puml with TimelineService/TimelineController components
  and their edges to PersonService and DocumentService

Refs #777
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.specify/rtm.md

@@ -59,3 +59,23 @@
 | REQ-014 | empty family-member list → empty result, no error | #776 | derive-person-life-events | `timeline/TimelineEventService#assembleDerivedEvents` | `DerivedEventsAssemblyTest#should_emit_zero_events_when_no_family_members` | Done |
 | REQ-015 | assembleDerivedEvents() annotated @Transactional(readOnly=true) | #776 | derive-person-life-events | `timeline/TimelineEventService#assembleDerivedEvents` | code-review check (annotation visible in source) | Done |
 | REQ-016 | no PII (names, dates) in log statements — only aggregate counts | #776 | derive-person-life-events | `timeline/TimelineEventService#assembleDerivedEvents` | log-audit: single log.debug with result.size() and persons.size() only | Done |
+| REQ-001 | GET /api/timeline requires READ_ALL permission; 401 unauthenticated, 403 wrong permission | #777 | timeline-assembly | `timeline/TimelineController#getTimeline` | `TimelineControllerTest#returns_401_when_unauthenticated`, `#returns_403_when_authenticated_without_read_all`, `#returns_200_with_read_all_permission` | Done |
+| REQ-002 | within-band sort: precision rank desc (DAY>MONTH>SEASON>YEAR>APPROX), then date asc, then title alpha, then id tiebreak | #777 | timeline-assembly | `timeline/TimelineService#WITHIN_BAND_ORDER` | `TimelineServiceTest#within_band_order_day_precision_sorts_before_year`, `#within_band_order_same_precision_and_date_sorts_alphabetically`, `#within_band_order_same_title_uses_document_id_as_tiebreak`, `#test5_day_precision_sorts_before_year_in_same_year_band`, `#test6_same_precision_same_date_sorted_alphabetically_by_title` | Done |
+| REQ-003 | null eventDate OR UNKNOWN precision → undated bucket (never in a year band) | #777 | timeline-assembly | `timeline/TimelineService#bucketByYear` | `TimelineServiceTest#test3a_null_date_letter_goes_to_undated`, `#test3b_unknown_precision_letter_goes_to_undated` | Done |
+| REQ-004 | RANGE events placed in start-year band only; null eventDateEnd does not crash; start year outside [fromYear,toYear] → excluded | #777 | timeline-assembly | `timeline/TimelineService#assembleCuratedEvents` | `TimelineServiceTest#test7a_range_event_placed_only_in_start_year_band`, `#test7b_range_event_with_null_eventDateEnd_does_not_crash`, `#test8_range_event_excluded_when_start_year_before_fromYear`, `#test15_range_event_start_year_equal_to_fromYear_is_included` | Done |
+| REQ-005 | null sender and null senderText on a document → senderName="" in the TimelineEntryDTO | #777 | timeline-assembly | `timeline/TimelineService#toLetterEntry` | `TimelineServiceTest#test4_letter_with_null_sender_and_null_senderText_produces_empty_names` | Done |
+| REQ-006 | personId filter: include document when personId is sender OR receiver | #777 | timeline-assembly | `timeline/TimelineService#fetchDocuments` | `TimelineServiceTest#test11_personId_scoping_deduplicates_letter_appearing_as_sender_and_receiver` | Done |
+| REQ-007 | documents domain letters always included (no type filter applied to LETTER kind) | #777 | timeline-assembly | `timeline/TimelineService#fetchDocuments`, `#assemble` | `TimelineServiceTest#test9a_type_filter_does_not_exclude_letters_but_excludes_wrong_type_events`, `#test1_empty_archive_returns_empty_dto`, `#test2_one_year_letter_returns_one_year_band` | Done |
+| REQ-008 | personId filter dedup: sender+receiver same person → document appears exactly once | #777 | timeline-assembly | `timeline/TimelineService#fetchDocuments` | `TimelineServiceTest#test11_personId_scoping_deduplicates_letter_appearing_as_sender_and_receiver` | Done |
+| REQ-009 | type filter applies to events only; letters (LETTER kind) always pass | #777 | timeline-assembly | `timeline/TimelineService#assembleCuratedEvents`, `#assembleDerivedEventsLayer` | `TimelineServiceTest#test9a_type_filter_does_not_exclude_letters_but_excludes_wrong_type_events` | Done |
+| REQ-010 | generation filter: PersonService.getPersonsByGeneration(N) used to build person-id set; filters all three layers | #777 | timeline-assembly | `timeline/TimelineService#assemble`, `person/PersonService#getPersonsByGeneration`, `person/PersonRepository#findByGeneration` | `TimelineServiceTest#test9b_generation_filter_includes_letter_when_sender_matches_generation`, `TimelineServiceIntegrationTest#findByGeneration_returns_matching_persons`, `#findByGeneration_returns_empty_list_not_npe_when_no_match`, `#findByGeneration_does_not_return_null_generation_persons` | Done |
+| REQ-011 | fromYear/toYear inclusive year-range filter; single-year window (fromYear==toYear); one-sided filter (fromYear only) | #777 | timeline-assembly | `timeline/TimelineService#passesYearFilter` | `TimelineServiceTest#test9c_fromYear_toYear_inclusive_single_year_window`, `#test16_fromYear_without_toYear_returns_all_items_from_that_year_onwards` | Done |
+| REQ-012 | combined filters AND logic — entry must pass all active filters | #777 | timeline-assembly | `timeline/TimelineService#assemble` | `TimelineServiceTest#test10_adversarial_and_logic_neither_event_passes_both_filters`, `#test12_personId_plus_generation_filter_returns_empty_when_generations_do_not_match` | Done |
+| REQ-013 | empty archive (no events, no persons, no documents) → TimelineDTO { years=[], undated=[] } | #777 | timeline-assembly | `timeline/TimelineService#assemble` | `TimelineServiceTest#test1_empty_archive_returns_empty_dto` | Done |
+| REQ-014 | unauthenticated request → 401 Unauthorized | #777 | timeline-assembly | `timeline/TimelineController#getTimeline` | `TimelineControllerTest#returns_401_when_unauthenticated` | Done |
+| REQ-015 | authenticated without READ_ALL → 403 Forbidden | #777 | timeline-assembly | `timeline/TimelineController#getTimeline` | `TimelineControllerTest#returns_403_when_authenticated_without_read_all` | Done |
+| REQ-016 | fromYear > toYear → 400 Bad Request | #777 | timeline-assembly | `timeline/TimelineService#assemble` | `TimelineServiceTest#fromYear_greater_than_toYear_throws_bad_request`, `TimelineControllerTest#returns_400_when_fromYear_greater_than_toYear` | Done |
+| REQ-017 | generation < 0 → 400 Bad Request (@Min(0) on controller param) | #777 | timeline-assembly | `timeline/TimelineController#getTimeline` | `TimelineControllerTest#returns_400_when_generation_is_negative` | Done |
+| REQ-018 | unknown EventType string → 400 Bad Request (Spring enum binding) | #777 | timeline-assembly | `timeline/TimelineController#getTimeline` | `TimelineControllerTest#returns_400_on_bad_type_value` | Done |
+| REQ-019 | unknown personId → 404 Not Found | #777 | timeline-assembly | `timeline/TimelineService#assemble` | `TimelineControllerTest#returns_404_when_person_not_found` | Done |
+| REQ-020 | null-generation persons excluded from generation-filter results | #777 | timeline-assembly | `person/PersonRepository#findByGeneration` | `TimelineServiceTest#test13_null_generation_sender_not_returned_by_generation_filter`, `TimelineServiceIntegrationTest#findByGeneration_does_not_return_null_generation_persons` | Done |