refactor: fix bugs et réduire duplication + extraire modales BrowseComponent

- fix(dto): ajouter @IsEmail() sur contactFunctionalEmail/TechnicalEmail dans UpdateApiEntryDto
- fix(docs): corriger stringify des erreurs (String(error) → error.message)
- refactor(mapper): extraire toApiEntryListItem() dans api-entry.mapper.ts partagé
- refactor(categories): supprimer CONVENTION_LABELS et toApiEntryListItem locaux dupliqués
- refactor(browse): extraire CategoryFormModalComponent et CategoryDeleteModalComponent
- refactor(api-detail): convertir editPreviewTitle() en computed()

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

back/src/modules/apis/dto/update-api-entry.dto.ts

@@ -1,4 +1,4 @@
-import { IsString, IsOptional, IsUUID, IsIn, IsInt, Min } from 'class-validator';
+import { IsString, IsOptional, IsUUID, IsIn, IsInt, Min, IsEmail } from 'class-validator';
 import { Type } from 'class-transformer';
 import { ApiConvention } from '@datacat/shared';
 
@@ -49,7 +49,7 @@ export class UpdateApiEntryDto {
   @IsOptional()
   contactFunctionalEntity?: string;
 
-  @IsString()
+  @IsEmail()
   @IsOptional()
   contactFunctionalEmail?: string;
 
@@ -61,7 +61,7 @@ export class UpdateApiEntryDto {
   @IsOptional()
   contactTechnicalEntity?: string;
 
-  @IsString()
+  @IsEmail()
   @IsOptional()
   contactTechnicalEmail?: string;
 }