fix: resolve all 47 svelte-check errors and 10 a11y warnings

Root cause 1 — OpenAPI types: add @Schema(requiredMode=REQUIRED) to
non-nullable fields on Person, Tag, Document, AppUser, UserGroup;
regenerate api.ts so required fields are no longer optional.

Root cause 2 — Stale types: api.ts regenerated, picking up the Tag
endpoint fix from commit 62189d8 (List<Tag> instead of List<String>).

Root cause 3 — openapi-fetch error pattern: replace `if (apiError)`
(broken when error type is never/undefined) with `if (!result.response.ok)`
across all +page.server.ts files. Cast error via `unknown` to satisfy TS.

Root cause 4 — FormData casts: add `as string` / `as string[]` to
FormData.get() / FormData.getAll() calls in admin/+page.server.ts.

Standalone fixes:
- +page.server.ts: return error field so home page template compiles
- documents/[id]/+page.svelte: type loadFile param, remove invalid iframe `type`
- conversations: type documents as Document[] instead of unknown[]
- persons/[id]: non-null assert person data after ok-check

a11y: aria-label on all icon-only buttons in TagInput and admin page,
replace invalid <label> with <p> for compound controls, remove autofocus.

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

backend/src/main/java/org/raddatz/familienarchiv/model/AppUser.java

@@ -8,6 +8,7 @@ import org.raddatz.familienarchiv.dto.CreateUserRequest;
 import org.springframework.security.crypto.password.PasswordEncoder;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
+import io.swagger.v3.oas.annotations.media.Schema;
 
 import java.time.LocalDateTime;
 import java.util.HashSet;
@@ -24,9 +25,11 @@ public class AppUser {
 
     @Id
     @GeneratedValue(strategy = GenerationType.UUID)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private UUID id;
 
     @Column(unique = true, nullable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private String username;
 
     @Column(nullable = false)
@@ -36,15 +39,18 @@ public class AppUser {
     private String email;
 
     @Builder.Default
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private boolean enabled = true; // Um User zu sperren ohne sie zu löschen
 
     // Ein User kann in mehreren Gruppen sein
     @ManyToMany(fetch = FetchType.EAGER)
     @JoinTable(name = "users_groups", joinColumns = @JoinColumn(name = "user_id"), inverseJoinColumns = @JoinColumn(name = "group_id"))
     @Builder.Default
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private Set<UserGroup> groups = new HashSet<>();
 
     @CreationTimestamp
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private LocalDateTime createdAt;
 
     public boolean hasPermission(String permission) {

backend/src/main/java/org/raddatz/familienarchiv/model/Document.java

@@ -6,6 +6,7 @@ import org.hibernate.annotations.CreationTimestamp;
 import org.hibernate.annotations.UpdateTimestamp;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import io.swagger.v3.oas.annotations.media.Schema;
 
 import java.time.LocalDate;
 import java.time.LocalDateTime;
@@ -23,9 +24,11 @@ public class Document {
 
     @Id
     @GeneratedValue(strategy = GenerationType.UUID)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private UUID id;
 
     @Column(nullable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private String title;
 
     // Der Dateiname im S3 (oder Pfad)
@@ -38,11 +41,13 @@ public class Document {
 
     // Originaler Dateiname beim Upload (z.B. "Brief_Oma_1940.pdf")
     @Column(name = "original_filename", nullable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private String originalFilename;
 
     // Der Status hilft uns beim Excel-Import Workflow
     @Enumerated(EnumType.STRING)
     @Column(nullable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private DocumentStatus status;
 
     // Metadaten aus dem Brief
@@ -70,9 +75,11 @@ public class Document {
 
     @CreationTimestamp
     @Column(updatable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private LocalDateTime createdAt;
 
     @UpdateTimestamp
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private LocalDateTime updatedAt;
 
     @ManyToMany(fetch = FetchType.EAGER)

backend/src/main/java/org/raddatz/familienarchiv/model/Person.java

@@ -1,5 +1,6 @@
 package org.raddatz.familienarchiv.model;
 
+import io.swagger.v3.oas.annotations.media.Schema;
 import jakarta.persistence.*;
 import lombok.*;
 
@@ -14,12 +15,15 @@ public class Person {
 
     @Id
     @GeneratedValue(strategy = GenerationType.UUID)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private UUID id;
 
     @Column(nullable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private String firstName;
 
     @Column(nullable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private String lastName;
 
     // Optional: Aliasse für die Suche (z.B. "Opa Hans")

backend/src/main/java/org/raddatz/familienarchiv/model/Tag.java

@@ -2,6 +2,7 @@ package org.raddatz.familienarchiv.model;
 
 import java.util.UUID;
 
+import io.swagger.v3.oas.annotations.media.Schema;
 import jakarta.persistence.*;
 import lombok.*;
 
@@ -13,8 +14,10 @@ import lombok.*;
 public class Tag {
     @Id
     @GeneratedValue(strategy = GenerationType.UUID)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private UUID id;
 
     @Column(unique = true, nullable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private String name;
 }

backend/src/main/java/org/raddatz/familienarchiv/model/UserGroup.java

@@ -1,5 +1,6 @@
 package org.raddatz.familienarchiv.model;
 
+import io.swagger.v3.oas.annotations.media.Schema;
 import jakarta.persistence.*;
 import lombok.*;
 
@@ -17,9 +18,11 @@ public class UserGroup {
 
     @Id
     @GeneratedValue(strategy = GenerationType.UUID)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private UUID id;
 
     @Column(unique = true, nullable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private String name; // z.B. "Admins", "Familie Müller"
 
     // Wir speichern Rechte als einfache Strings (z.B. "READ_ALL", "WRITE_DOCUMENTS")
@@ -27,5 +30,6 @@ public class UserGroup {
     @CollectionTable(name = "group_permissions", joinColumns = @JoinColumn(name = "group_id"))
     @Column(name = "permission")
     @Builder.Default
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private Set<String> permissions = new HashSet<>();
 }