feat: Projekt-Verwaltung verbessern — Archivieren, Loeschen, Wiederherstellen

- Backend: Restore-Endpoint (POST /projects/{id}/restore) und
  Hard-Delete-Endpoint (DELETE /projects/{id}/permanent) hinzugefuegt
- Frontend: Dreistufiger Dialog (Archivieren / Endgueltig loeschen mit
  Bestaetigungsdialog) statt einfachem Loeschen
- Archivierte Projekte aufklappbar in der Projektliste mit
  Wiederherstellen-Button
- CustomerTypeSelector entfernt (redundant seit Multi-Projekt)
- Default tenantId von 'default' auf UUID geaendert (Backend-400-Fix)
- SQL-Cast :state::jsonb durch CAST(:state AS jsonb) ersetzt (SQLAlchemy-Fix)
- snake_case/camelCase-Mapping fuer Backend-Response (NaN-Datum-Fix)
- projectInfo wird beim Laden vom Backend geholt (Header zeigt Projektname)
- API-Client erzeugt sich on-demand (Race-Condition-Fix fuer Projektliste)

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

admin-compliance/lib/sdk/api-client.ts

@@ -600,9 +600,9 @@ export class SDKApiClient {
   /**
    * List all projects for the current tenant
    */
-  async listProjects(): Promise<{ projects: ProjectInfo[]; total: number }> {
+  async listProjects(includeArchived = true): Promise<{ projects: ProjectInfo[]; total: number }> {
     const response = await this.fetchWithRetry<{ projects: ProjectInfo[]; total: number }>(
-      `${this.baseUrl}/projects?tenant_id=${encodeURIComponent(this.tenantId)}`,
+      `${this.baseUrl}/projects?tenant_id=${encodeURIComponent(this.tenantId)}&include_archived=${includeArchived}`,
       {
         method: 'GET',
         headers: {
@@ -664,6 +664,23 @@ export class SDKApiClient {
     return response
   }
 
+  /**
+   * Get a single project by ID
+   */
+  async getProject(projectId: string): Promise<ProjectInfo> {
+    const response = await this.fetchWithRetry<ProjectInfo>(
+      `${this.baseUrl}/projects/${projectId}?tenant_id=${encodeURIComponent(this.tenantId)}`,
+      {
+        method: 'GET',
+        headers: {
+          'Content-Type': 'application/json',
+          'X-Tenant-ID': this.tenantId,
+        },
+      }
+    )
+    return response
+  }
+
   /**
    * Archive (soft-delete) a project
    */
@@ -680,6 +697,39 @@ export class SDKApiClient {
     )
   }
 
+  /**
+   * Restore an archived project
+   */
+  async restoreProject(projectId: string): Promise<ProjectInfo> {
+    const response = await this.fetchWithRetry<ProjectInfo>(
+      `${this.baseUrl}/projects/${projectId}/restore?tenant_id=${encodeURIComponent(this.tenantId)}`,
+      {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          'X-Tenant-ID': this.tenantId,
+        },
+      }
+    )
+    return response
+  }
+
+  /**
+   * Permanently delete a project and all data
+   */
+  async permanentlyDeleteProject(projectId: string): Promise<void> {
+    await this.fetchWithRetry<{ success: boolean }>(
+      `${this.baseUrl}/projects/${projectId}/permanent?tenant_id=${encodeURIComponent(this.tenantId)}`,
+      {
+        method: 'DELETE',
+        headers: {
+          'Content-Type': 'application/json',
+          'X-Tenant-ID': this.tenantId,
+        },
+      }
+    )
+  }
+
   /**
    * Health check
    */