feat(stamdata): admin stamdata maintenance editor (beheer)

Realizes ADR-0004's "future low-code editor that commits a PR": an
admin-only stamdata maintenance editor built on the stamdata-as-code
foundation.

Backend: `professions` moves from a hardcoded C# dictionary to an embedded
`professions.json` data-file (typed as `ProfessionMapping`) with valid-time
(geldigVan/geldigTot, half-open). A generic, reflection-driven
StamdataCatalog/StamdataTable/StamdataFile describes every table so one
endpoint pair + one grid editor serve all of them; add a table in one line.
Two read-only, admin-gated endpoints (GET /stamdata, GET /stamdata/{table}
?peildatum=) — no runtime write path. Generic build gate
`Every_catalog_table_is_valid` (keys non-blank, no overlapping validity,
well-formed windows).

Frontend: new `beheer` context (route beheer/stamdata, capabilityGuard
'stamdata:edit'). A schema-driven grid editor edits rows locally; download()
emits {table}.json for the admin to commit as a reviewed PR (no mutation
command — the CI build + StamdataValidationTests stay the authority).

Full gate GREEN both sides; gen:api leaves no drift; new stamdata story
passes axe. See WP-29 + ADR-0004.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/shared/infrastructure/api-client.ts

@@ -263,6 +263,102 @@ export class ApiClient {
         return Promise.resolve<IntakePolicyDto>(null as any);
     }
 
+    /**
+     * @return OK
+     */
+    stamdataTables(): Promise<StamdataTableSummaryDto[]> {
+        let url_ = this.baseUrl + "/api/v1/stamdata";
+        url_ = url_.replace(/[?&]$/, "");
+
+        let options_: RequestInit = {
+            method: "GET",
+            headers: {
+                "Accept": "application/json"
+            }
+        };
+
+        return this.http.fetch(url_, options_).then((_response: Response) => {
+            return this.processStamdataTables(_response);
+        });
+    }
+
+    protected processStamdataTables(response: Response): Promise<StamdataTableSummaryDto[]> {
+        const status = response.status;
+        let _headers: any = {}; if (response.headers && response.headers.forEach) { response.headers.forEach((v: any, k: any) => _headers[k] = v); };
+        if (status === 200) {
+            return response.text().then((_responseText) => {
+            let result200: any = null;
+            result200 = _responseText === "" ? null : JSON.parse(_responseText, this.jsonParseReviver) as StamdataTableSummaryDto[];
+            return result200;
+            });
+        } else if (status === 403) {
+            return response.text().then((_responseText) => {
+            let result403: any = null;
+            result403 = _responseText === "" ? null : JSON.parse(_responseText, this.jsonParseReviver) as ProblemDetails;
+            return throwException("Forbidden", status, _responseText, _headers, result403);
+            });
+        } else if (status !== 200 && status !== 204) {
+            return response.text().then((_responseText) => {
+            return throwException("An unexpected server error occurred.", status, _responseText, _headers);
+            });
+        }
+        return Promise.resolve<StamdataTableSummaryDto[]>(null as any);
+    }
+
+    /**
+     * @param peildatum (optional) 
+     * @return OK
+     */
+    stamdataTable(table: string, peildatum?: string | undefined): Promise<StamdataTableDto> {
+        let url_ = this.baseUrl + "/api/v1/stamdata/{table}?";
+        if (table === undefined || table === null)
+            throw new globalThis.Error("The parameter 'table' must be defined.");
+        url_ = url_.replace("{table}", encodeURIComponent("" + table));
+        if (peildatum === null)
+            throw new globalThis.Error("The parameter 'peildatum' cannot be null.");
+        else if (peildatum !== undefined)
+            url_ += "peildatum=" + encodeURIComponent("" + peildatum) + "&";
+        url_ = url_.replace(/[?&]$/, "");
+
+        let options_: RequestInit = {
+            method: "GET",
+            headers: {
+                "Accept": "application/json"
+            }
+        };
+
+        return this.http.fetch(url_, options_).then((_response: Response) => {
+            return this.processStamdataTable(_response);
+        });
+    }
+
+    protected processStamdataTable(response: Response): Promise<StamdataTableDto> {
+        const status = response.status;
+        let _headers: any = {}; if (response.headers && response.headers.forEach) { response.headers.forEach((v: any, k: any) => _headers[k] = v); };
+        if (status === 200) {
+            return response.text().then((_responseText) => {
+            let result200: any = null;
+            result200 = _responseText === "" ? null : JSON.parse(_responseText, this.jsonParseReviver) as StamdataTableDto;
+            return result200;
+            });
+        } else if (status === 403) {
+            return response.text().then((_responseText) => {
+            let result403: any = null;
+            result403 = _responseText === "" ? null : JSON.parse(_responseText, this.jsonParseReviver) as ProblemDetails;
+            return throwException("Forbidden", status, _responseText, _headers, result403);
+            });
+        } else if (status === 404) {
+            return response.text().then((_responseText) => {
+            return throwException("Not Found", status, _responseText, _headers);
+            });
+        } else if (status !== 200 && status !== 204) {
+            return response.text().then((_responseText) => {
+            return throwException("An unexpected server error occurred.", status, _responseText, _headers);
+            });
+        }
+        return Promise.resolve<StamdataTableDto>(null as any);
+    }
+
     /**
      * @return OK
      */
@@ -1858,6 +1954,28 @@ export interface SaveOrgTemplateRequest {
     draft?: OrgTemplateDto;
 }
 
+export interface StamdataColumnDto {
+    name?: string | undefined;
+    type?: string | undefined;
+    isKey?: boolean;
+    options?: string[] | undefined;
+}
+
+export interface StamdataTableDto {
+    id?: string | undefined;
+    label?: string | undefined;
+    columns?: StamdataColumnDto[] | undefined;
+    temporal?: boolean;
+    rows?: any[] | undefined;
+}
+
+export interface StamdataTableSummaryDto {
+    id?: string | undefined;
+    label?: string | undefined;
+    columns?: StamdataColumnDto[] | undefined;
+    temporal?: boolean;
+}
+
 export interface SubOrgSummaryDto {
     subOrgId?: string | undefined;
     orgName?: string | undefined;