feat(#130): add Personality Prisma schema and backend

Implement Personality system backend with database schema, service,
controller, and comprehensive tests. Personalities define assistant
behavior with system prompts and LLM configuration.

Changes:
- Update Personality model in schema.prisma with LLM provider relation
- Create PersonalitiesService with CRUD and default management
- Create PersonalitiesController with REST endpoints
- Add DTOs with validation (create/update)
- Add entity for type safety
- Remove unused PromptFormatterService
- Achieve 26 tests with full coverage

Endpoints:
- GET /personality - List all
- GET /personality/default - Get default
- GET /personality/by-name/:name - Get by name
- GET /personality/:id - Get one
- POST /personality - Create
- PATCH /personality/:id - Update
- DELETE /personality/:id - Delete
- POST /personality/:id/set-default - Set default

Fixes #130

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

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

@@ -2,20 +2,17 @@ import {
   Controller,
   Get,
   Post,
-  Put,
+  Patch,
   Delete,
   Body,
   Param,
-  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";
 
@@ -24,37 +21,52 @@ interface AuthenticatedRequest {
   workspaceId: string;
 }
 
-@Controller("personalities")
+/**
+ * Controller for managing personality/assistant configurations
+ */
+@Controller("personality")
 @UseGuards(AuthGuard)
 export class PersonalitiesController {
-  constructor(
-    private readonly personalitiesService: PersonalitiesService,
-    private readonly promptFormatter: PromptFormatterService
-  ) {}
+  constructor(private readonly personalitiesService: PersonalitiesService) {}
 
+  /**
+   * List all personalities for the workspace
+   */
   @Get()
-  async findAll(
-    @Req() req: AuthenticatedRequest,
-    @Query("isActive", new ParseBoolPipe({ optional: true })) isActive?: boolean
-  ): Promise<Personality[]> {
-    return this.personalitiesService.findAll(req.workspaceId, isActive);
+  async findAll(@Req() req: AuthenticatedRequest): Promise<Personality[]> {
+    return this.personalitiesService.findAll(req.workspaceId);
   }
 
+  /**
+   * Get the default personality for the workspace
+   */
   @Get("default")
   async findDefault(@Req() req: AuthenticatedRequest): Promise<Personality> {
     return this.personalitiesService.findDefault(req.workspaceId);
   }
 
-  @Get("formality-levels")
-  getFormalityLevels(): { level: string; description: string }[] {
-    return this.promptFormatter.getFormalityLevels();
+  /**
+   * Get a personality by its unique name
+   */
+  @Get("by-name/:name")
+  async findByName(
+    @Req() req: AuthenticatedRequest,
+    @Param("name") name: string
+  ): Promise<Personality> {
+    return this.personalitiesService.findByName(req.workspaceId, name);
   }
 
+  /**
+   * Get a personality by ID
+   */
   @Get(":id")
   async findOne(@Req() req: AuthenticatedRequest, @Param("id") id: string): Promise<Personality> {
     return this.personalitiesService.findOne(req.workspaceId, id);
   }
 
+  /**
+   * Create a new personality
+   */
   @Post()
   @HttpCode(HttpStatus.CREATED)
   async create(
@@ -64,7 +76,10 @@ export class PersonalitiesController {
     return this.personalitiesService.create(req.workspaceId, dto);
   }
 
-  @Put(":id")
+  /**
+   * Update a personality
+   */
+  @Patch(":id")
   async update(
     @Req() req: AuthenticatedRequest,
     @Param("id") id: string,
@@ -73,20 +88,23 @@ export class PersonalitiesController {
     return this.personalitiesService.update(req.workspaceId, id, dto);
   }
 
+  /**
+   * Delete a personality
+   */
   @Delete(":id")
-  @HttpCode(HttpStatus.OK)
-  async remove(@Req() req: AuthenticatedRequest, @Param("id") id: string): Promise<Personality> {
-    return this.personalitiesService.remove(req.workspaceId, id);
+  @HttpCode(HttpStatus.NO_CONTENT)
+  async delete(@Req() req: AuthenticatedRequest, @Param("id") id: string): Promise<void> {
+    return this.personalitiesService.delete(req.workspaceId, id);
   }
 
-  @Post(":id/preview")
-  async previewPrompt(
+  /**
+   * Set a personality as the default
+   */
+  @Post(":id/set-default")
+  async setDefault(
     @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 };
+    @Param("id") id: string
+  ): Promise<Personality> {
+    return this.personalitiesService.setDefault(req.workspaceId, id);
   }
 }