feat: add HelpText model, service, and controller for dynamic help text management

backend/src/help-texts/help-texts.controller.ts

@@ -0,0 +1,28 @@
+import { Body, Controller, Get, Param, Put } from '@nestjs/common';
+import { CurrentUser } from '../auth/decorators/current-user.decorator';
+import { Roles } from '../auth/decorators/roles.decorator';
+import { UpsertHelpTextDto } from './dto/upsert-help-text.dto';
+import { HelpTextsService } from './help-texts.service';
+
+@Controller('help-texts')
+export class HelpTextsController {
+  constructor(private readonly helpTextsService: HelpTextsService) {}
+
+  @Get(':key')
+  getByKey(
+    @Param('key') key: string,
+    @CurrentUser() user: { role?: string },
+  ) {
+    return this.helpTextsService.getResolvedByKey(key, user?.role);
+  }
+
+  @Roles('admin')
+  @Put(':key/:scope')
+  upsert(
+    @Param('key') key: string,
+    @Param('scope') scope: string,
+    @Body() dto: UpsertHelpTextDto,
+  ) {
+    return this.helpTextsService.upsert(key, scope, dto);
+  }
+}