fix(orchestrator): resolve all M6 remediation issues (#260-#269)

Addresses all 10 quality remediation issues for the orchestrator module:

TypeScript & Type Safety:
- #260: Fix TypeScript compilation errors in tests
- #261: Replace explicit 'any' types with proper typed mocks

Error Handling & Reliability:
- #262: Fix silent cleanup failures - return structured results
- #263: Fix silent Valkey event parsing failures with proper error handling
- #266: Improve error context in Docker operations
- #267: Fix secret scanner false negatives on file read errors
- #268: Fix worktree cleanup error swallowing

Testing & Quality:
- #264: Add queue integration tests (coverage 15% → 85%)
- #265: Fix Prettier formatting violations
- #269: Update outdated TODO comments

All tests passing (406/406), TypeScript compiles cleanly, ESLint clean.

Fixes #260, Fixes #261, Fixes #262, Fixes #263, Fixes #264
Fixes #265, Fixes #266, Fixes #267, Fixes #268, Fixes #269

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

apps/orchestrator/src/api/agents/dto/spawn-agent.dto.ts

@@ -0,0 +1,64 @@
+import {
+  IsString,
+  IsNotEmpty,
+  IsEnum,
+  ValidateNested,
+  IsArray,
+  IsOptional,
+  ArrayNotEmpty,
+  IsIn,
+} from "class-validator";
+import { Type } from "class-transformer";
+import { AgentType } from "../../../spawner/types/agent-spawner.types";
+import { GateProfileType } from "../../../coordinator/types/gate-config.types";
+
+/**
+ * Context DTO for agent spawn request
+ */
+export class AgentContextDto {
+  @IsString()
+  @IsNotEmpty()
+  repository!: string;
+
+  @IsString()
+  @IsNotEmpty()
+  branch!: string;
+
+  @IsArray()
+  @ArrayNotEmpty()
+  @IsString({ each: true })
+  workItems!: string[];
+
+  @IsArray()
+  @IsOptional()
+  @IsString({ each: true })
+  skills?: string[];
+}
+
+/**
+ * Request DTO for spawning an agent
+ */
+export class SpawnAgentDto {
+  @IsString()
+  @IsNotEmpty()
+  taskId!: string;
+
+  @IsEnum(["worker", "reviewer", "tester"])
+  agentType!: AgentType;
+
+  @ValidateNested()
+  @Type(() => AgentContextDto)
+  context!: AgentContextDto;
+
+  @IsOptional()
+  @IsIn(["strict", "standard", "minimal", "custom"])
+  gateProfile?: GateProfileType;
+}
+
+/**
+ * Response DTO for spawn agent endpoint
+ */
+export class SpawnAgentResponseDto {
+  agentId!: string;
+  status!: "spawning" | "queued";
+}