feat(api): implement personalities CRUD API with DTOs and Prisma model

- Add GET /api/personalities?isActive=true|false (list with optional filter)
- Add GET /api/personalities/default (default personality endpoint)
- Add GET /api/personalities/:id (single personality by ID)
- Add POST /api/personalities (create personality)
- Add PATCH /api/personalities/:id (update personality)
- Add DELETE /api/personalities/:id (delete personality)
- Add POST /api/personalities/:id/set-default (convenience set-default)
- Add tone and formalityLevel fields to Prisma Personality model
- Add migration 20260227000000_add_personality_tone_formality
- Map Prisma field names to frontend API contract (systemPrompt->systemPromptTemplate, isEnabled->isActive)
- Apply WorkspaceGuard + PermissionGuard per project patterns
- Return { success: true, data } wrapper for list endpoint
- Add PersonalityQueryDto for isActive filter support
- Update spec files to reflect new field mapping and response shape

Resolves frontend 404 on /api/personalities

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

apps/api/src/personalities/dto/create-personality.dto.ts

@@ -1,59 +1,38 @@
-import {
-  IsString,
-  IsOptional,
-  IsBoolean,
-  IsNumber,
-  IsInt,
-  IsUUID,
-  MinLength,
-  MaxLength,
-  Min,
-  Max,
-} from "class-validator";
+import { FormalityLevel } from "@prisma/client";
+import { IsString, IsEnum, IsOptional, IsBoolean, MinLength, MaxLength } from "class-validator";
 
 /**
- * DTO for creating a new personality/assistant configuration
+ * DTO for creating a new personality
+ * Field names match the frontend API contract from @mosaic/shared Personality type.
  */
 export class CreatePersonalityDto {
-  @IsString()
-  @MinLength(1)
-  @MaxLength(100)
-  name!: string; // unique identifier slug
-
-  @IsString()
-  @MinLength(1)
-  @MaxLength(200)
-  displayName!: string; // human-readable name
+  @IsString({ message: "name must be a string" })
+  @MinLength(1, { message: "name must not be empty" })
+  @MaxLength(255, { message: "name must not exceed 255 characters" })
+  name!: string;
 
   @IsOptional()
-  @IsString()
-  @MaxLength(1000)
+  @IsString({ message: "description must be a string" })
+  @MaxLength(2000, { message: "description must not exceed 2000 characters" })
   description?: string;
 
-  @IsString()
-  @MinLength(10)
-  systemPrompt!: string;
+  @IsString({ message: "tone must be a string" })
+  @MinLength(1, { message: "tone must not be empty" })
+  @MaxLength(100, { message: "tone must not exceed 100 characters" })
+  tone!: string;
+
+  @IsEnum(FormalityLevel, { message: "formalityLevel must be a valid FormalityLevel" })
+  formalityLevel!: FormalityLevel;
+
+  @IsString({ message: "systemPromptTemplate must be a string" })
+  @MinLength(1, { message: "systemPromptTemplate must not be empty" })
+  systemPromptTemplate!: string;
 
   @IsOptional()
-  @IsNumber()
-  @Min(0)
-  @Max(2)
-  temperature?: number; // null = use provider default
-
-  @IsOptional()
-  @IsInt()
-  @Min(1)
-  maxTokens?: number; // null = use provider default
-
-  @IsOptional()
-  @IsUUID("4")
-  llmProviderInstanceId?: string; // FK to LlmProviderInstance
-
-  @IsOptional()
-  @IsBoolean()
+  @IsBoolean({ message: "isDefault must be a boolean" })
   isDefault?: boolean;
 
   @IsOptional()
-  @IsBoolean()
-  isEnabled?: boolean;
+  @IsBoolean({ message: "isActive must be a boolean" })
+  isActive?: boolean;
 }