feat(relationship): editable relationships with LocalDate+DatePrecision dates and notes (#841)

Closes #837

Makes `PersonRelationship` fully editable (type, related person, dates, notes), migrates its dates from `Integer fromYear/toYear` to `LocalDate + DatePrecision` (mirroring the #773 person pattern, ADR-039 / V76), activates the previously-dead `notes` column, and gives the Zeitstrahl's derived **Heirat** events full date precision for free.

Both Open Decisions confirmed as adopted: **no `@Version`** (last-write-wins, single-writer archive) and **`DELETE` ownership-mismatch aligned 403 → 404** (anti-enumeration, matching the new `PUT`).

## What's in it
- **V78** migrates `person_relationships.from_year/to_year` → `from_date`/`to_date` + NOT-NULL `*_date_precision` (default `UNKNOWN`); pre-check abort on corrupt years, `YYYY-01-01`/`YEAR` backfill, 5 named CHECK constraints, year columns dropped.
- **`PUT /api/persons/{id}/relationships/{relId}`** (`@RequirePermission(WRITE_ALL)`) re-runs every create invariant (self / coherence / order / reverse-PARENT_OF / duplicate) and re-flags family membership; orientation preserved per viewpoint.
- New `ErrorCode.INVALID_RELATIONSHIP_DATES` registered in all four sites (§3.6).
- `TimelineEventService` sources the derived marriage date from `SPOUSE_OF.fromDate` + precision.
- Frontend: `RelationshipDateField` (DAY/MONTH/YEAR), upsert-capable `AddRelationshipForm` (pre-fill + notes + in-flight submit lock), `RelationshipChip` Edit affordance, `updateRelationship` server action, read-view date range + notes, `formatRelationshipDateRange` helper. `api.ts` regenerated.
- Docs: ADR-044, db-orm/db-relationships diagrams, DEPLOYMENT §5 deploy note, RTM REQ-001…REQ-019.

## Requirements
All 19 EARS requirements implemented red/green and marked `Done` in `.specify/rtm.md`.

## Test plan
- **Backend** (targeted, green): `RelationshipMigrationTest` (Testcontainers pg16, 8), `RelationshipServiceTest` (22), `RelationshipControllerTest` (15), `RelationshipServiceIntegrationTest` (real DB, 10), `DerivedEventsAssemblyTest` (17), `ArchitectureTest` (14); `clean package` builds.
- **Frontend** (green): `relationshipDates.spec.ts`, `AddRelationshipForm.svelte.spec.ts`, `RelationshipChip.svelte.spec.ts`, `PersonRelationshipsCard.svelte.test.ts`, `page.server.spec.ts`, `messages.spec.ts`. `npm run check` = 798 (below the ~834 baseline); `npm run lint` clean.

## Notes for reviewers
- **Spec deviation:** the edit form was built by making `AddRelationshipForm` upsert-capable rather than a duplicate `EditRelationshipForm` (DRY); RTM rows reference `AddRelationshipForm.svelte.spec.ts`.
- `api.ts` regenerated from the live spec; only relationship-relevant hunks remain (one springdoc `PageableObject` field-reorder pruned).
- **Deploy:** V78 is one-way and not rolling-deploy-safe — stop old JAR → start new JAR (Flyway runs first); targeted `pg_restore -t person_relationships` for rollback. No maintenance window.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Marcel <marcel@familienarchiv>
Reviewed-on: #841

frontend/src/lib/generated/api.ts

@@ -100,6 +100,22 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/api/persons/{id}/relationships/{relId}": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put: operations["updateRelationship"];
+        post?: never;
+        delete: operations["deleteRelationship"];
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/api/geschichten/{id}/items/reorder": {
         parameters: {
             query?: never;
@@ -1640,22 +1656,6 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
-    "/api/persons/{id}/relationships/{relId}": {
-        parameters: {
-            query?: never;
-            header?: never;
-            path?: never;
-            cookie?: never;
-        };
-        get?: never;
-        put?: never;
-        post?: never;
-        delete: operations["deleteRelationship"];
-        options?: never;
-        head?: never;
-        patch?: never;
-        trace?: never;
-    };
     "/api/persons/{id}/aliases/{aliasId}": {
         parameters: {
             query?: never;
@@ -1853,6 +1853,50 @@ export interface components {
             provisional: boolean;
             readonly displayName: string;
         };
+        RelationshipUpsertRequest: {
+            /** Format: uuid */
+            relatedPersonId: string;
+            /** @enum {string} */
+            relationType: "PARENT_OF" | "SPOUSE_OF" | "SIBLING_OF" | "FRIEND" | "COLLEAGUE" | "EMPLOYER" | "DOCTOR" | "NEIGHBOR" | "OTHER";
+            /** Format: date */
+            fromDate?: string;
+            /** @enum {string} */
+            fromDatePrecision?: "DAY" | "MONTH" | "SEASON" | "YEAR" | "RANGE" | "APPROX" | "UNKNOWN";
+            /** Format: date */
+            toDate?: string;
+            /** @enum {string} */
+            toDatePrecision?: "DAY" | "MONTH" | "SEASON" | "YEAR" | "RANGE" | "APPROX" | "UNKNOWN";
+            notes?: string;
+        };
+        RelationshipDTO: {
+            /** Format: uuid */
+            id: string;
+            /** Format: uuid */
+            personId: string;
+            /** Format: uuid */
+            relatedPersonId: string;
+            personDisplayName: string;
+            /** Format: int32 */
+            personBirthYear?: number;
+            /** Format: int32 */
+            personDeathYear?: number;
+            relatedPersonDisplayName: string;
+            /** Format: int32 */
+            relatedPersonBirthYear?: number;
+            /** Format: int32 */
+            relatedPersonDeathYear?: number;
+            /** @enum {string} */
+            relationType: "PARENT_OF" | "SPOUSE_OF" | "SIBLING_OF" | "FRIEND" | "COLLEAGUE" | "EMPLOYER" | "DOCTOR" | "NEIGHBOR" | "OTHER";
+            /** Format: date */
+            fromDate?: string;
+            /** @enum {string} */
+            fromDatePrecision: "DAY" | "MONTH" | "SEASON" | "YEAR" | "RANGE" | "APPROX" | "UNKNOWN";
+            /** Format: date */
+            toDate?: string;
+            /** @enum {string} */
+            toDatePrecision: "DAY" | "MONTH" | "SEASON" | "YEAR" | "RANGE" | "APPROX" | "UNKNOWN";
+            notes?: string;
+        };
         JourneyReorderDTO: {
             itemIds?: string[];
         };
@@ -2008,42 +2052,6 @@ export interface components {
             /** Format: uuid */
             targetId: string;
         };
-        CreateRelationshipRequest: {
-            /** Format: uuid */
-            relatedPersonId: string;
-            /** @enum {string} */
-            relationType: "PARENT_OF" | "SPOUSE_OF" | "SIBLING_OF" | "FRIEND" | "COLLEAGUE" | "EMPLOYER" | "DOCTOR" | "NEIGHBOR" | "OTHER";
-            /** Format: int32 */
-            fromYear?: number;
-            /** Format: int32 */
-            toYear?: number;
-            notes?: string;
-        };
-        RelationshipDTO: {
-            /** Format: uuid */
-            id: string;
-            /** Format: uuid */
-            personId: string;
-            /** Format: uuid */
-            relatedPersonId: string;
-            personDisplayName: string;
-            /** Format: int32 */
-            personBirthYear?: number;
-            /** Format: int32 */
-            personDeathYear?: number;
-            relatedPersonDisplayName: string;
-            /** Format: int32 */
-            relatedPersonBirthYear?: number;
-            /** Format: int32 */
-            relatedPersonDeathYear?: number;
-            /** @enum {string} */
-            relationType: "PARENT_OF" | "SPOUSE_OF" | "SIBLING_OF" | "FRIEND" | "COLLEAGUE" | "EMPLOYER" | "DOCTOR" | "NEIGHBOR" | "OTHER";
-            /** Format: int32 */
-            fromYear?: number;
-            /** Format: int32 */
-            toYear?: number;
-            notes?: string;
-        };
         PersonNameAliasDTO: {
             lastName: string;
             firstName?: string;
@@ -3200,6 +3208,54 @@ export interface operations {
             };
         };
     };
+    updateRelationship: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                id: string;
+                relId: string;
+            };
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": components["schemas"]["RelationshipUpsertRequest"];
+            };
+        };
+        responses: {
+            /** @description OK */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "*/*": components["schemas"]["RelationshipDTO"];
+                };
+            };
+        };
+    };
+    deleteRelationship: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                id: string;
+                relId: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description No Content */
+            204: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content?: never;
+            };
+        };
+    };
     reorderItems: {
         parameters: {
             query?: never;
@@ -3663,7 +3719,7 @@ export interface operations {
         };
         requestBody: {
             content: {
-                "application/json": components["schemas"]["CreateRelationshipRequest"];
+                "application/json": components["schemas"]["RelationshipUpsertRequest"];
             };
         };
         responses: {
@@ -5909,27 +5965,6 @@ export interface operations {
             };
         };
     };
-    deleteRelationship: {
-        parameters: {
-            query?: never;
-            header?: never;
-            path: {
-                id: string;
-                relId: string;
-            };
-            cookie?: never;
-        };
-        requestBody?: never;
-        responses: {
-            /** @description No Content */
-            204: {
-                headers: {
-                    [name: string]: unknown;
-                };
-                content?: never;
-            };
-        };
-    };
     removeAlias: {
         parameters: {
             query?: never;