feat(#82): add prompt formatter service to personality module

- Add PromptFormatterService for formatting system prompts based on personality
- Support context variable interpolation (userName, workspaceName, etc.)
- Add formality level modifiers (VERY_CASUAL to VERY_FORMAL)
- Add template validation for custom variables
- Add preview endpoint for formatted prompts
- Fix UpdatePersonalityDto to avoid @nestjs/mapped-types dependency
- Update PersonalitiesController with new endpoints
- Add comprehensive tests (33 passing tests)

Closes #82

apps/api/src/personalities/personalities.controller.ts

@@ -9,69 +9,81 @@ import {
   Query,
   UseGuards,
   Req,
+  ParseBoolPipe,
+  HttpCode,
+  HttpStatus,
 } from "@nestjs/common";
 import { AuthGuard } from "../auth/guards/auth.guard";
 import { PersonalitiesService } from "./personalities.service";
+import { PromptFormatterService, PromptContext } from "./services/prompt-formatter.service";
 import { CreatePersonalityDto, UpdatePersonalityDto } from "./dto";
 import { Personality } from "./entities/personality.entity";
 
+interface AuthenticatedRequest {
+  user: { id: string };
+  workspaceId: string;
+}
+
 @Controller("personalities")
 @UseGuards(AuthGuard)
 export class PersonalitiesController {
-  constructor(private readonly personalitiesService: PersonalitiesService) {}
+  constructor(
+    private readonly personalitiesService: PersonalitiesService,
+    private readonly promptFormatter: PromptFormatterService,
+  ) {}
 
-  /**
-   * Get all personalities for the current workspace
-   */
   @Get()
   async findAll(
-    @Req() req: any,
-    @Query("isActive") isActive: boolean = true,
+    @Req() req: AuthenticatedRequest,
+    @Query("isActive", new ParseBoolPipe({ optional: true })) isActive?: boolean,
   ): Promise<Personality[]> {
     return this.personalitiesService.findAll(req.workspaceId, isActive);
   }
 
-  /**
-   * Get the default personality for the current workspace
-   */
   @Get("default")
-  async findDefault(@Req() req: any): Promise<Personality> {
+  async findDefault(@Req() req: AuthenticatedRequest): Promise<Personality> {
     return this.personalitiesService.findDefault(req.workspaceId);
   }
 
-  /**
-   * Get a specific personality by ID
-   */
+  @Get("formality-levels")
+  getFormalityLevels(): Array<{ level: string; description: string }> {
+    return this.promptFormatter.getFormalityLevels();
+  }
+
   @Get(":id")
-  async findOne(@Req() req: any, @Param("id") id: string): Promise<Personality> {
+  async findOne(@Req() req: AuthenticatedRequest, @Param("id") id: string): Promise<Personality> {
     return this.personalitiesService.findOne(req.workspaceId, id);
   }
 
-  /**
-   * Create a new personality
-   */
   @Post()
-  async create(@Req() req: any, @Body() dto: CreatePersonalityDto): Promise<Personality> {
+  @HttpCode(HttpStatus.CREATED)
+  async create(@Req() req: AuthenticatedRequest, @Body() dto: CreatePersonalityDto): Promise<Personality> {
     return this.personalitiesService.create(req.workspaceId, dto);
   }
 
-  /**
-   * Update an existing personality
-   */
   @Put(":id")
   async update(
-    @Req() req: any,
+    @Req() req: AuthenticatedRequest,
     @Param("id") id: string,
     @Body() dto: UpdatePersonalityDto,
   ): Promise<Personality> {
     return this.personalitiesService.update(req.workspaceId, id, dto);
   }
 
-  /**
-   * Delete a personality
-   */
   @Delete(":id")
-  async remove(@Req() req: any, @Param("id") id: string): Promise<Personality> {
+  @HttpCode(HttpStatus.OK)
+  async remove(@Req() req: AuthenticatedRequest, @Param("id") id: string): Promise<Personality> {
     return this.personalitiesService.remove(req.workspaceId, id);
   }
+
+  @Post(":id/preview")
+  async previewPrompt(
+    @Req() req: AuthenticatedRequest,
+    @Param("id") id: string,
+    @Body() context?: PromptContext,
+  ): Promise<{ systemPrompt: string }> {
+    const personality = await this.personalitiesService.findOne(req.workspaceId, id);
+    const { systemPrompt } = this.promptFormatter.formatPrompt(personality, context);
+    return { systemPrompt };
+  }
 }