fix(SEC-ORCH-28+29): Add Valkey connection timeout + workItems MaxLength

SEC-ORCH-28: Add connectTimeout (5000ms default) and commandTimeout
(3000ms default) to Valkey/Redis client to prevent indefinite connection
hangs. Both are configurable via VALKEY_CONNECT_TIMEOUT_MS and
VALKEY_COMMAND_TIMEOUT_MS environment variables.

SEC-ORCH-29: Add @ArrayMaxSize(50) and @MaxLength(2000) to workItems
in AgentContextDto to prevent memory exhaustion from unbounded input.
Also adds @ArrayMaxSize(20) and @MaxLength(200) to skills array.

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

apps/orchestrator/src/config/orchestrator.config.ts

@@ -8,6 +8,8 @@ export const orchestratorConfig = registerAs("orchestrator", () => ({
     port: parseInt(process.env.VALKEY_PORT ?? "6379", 10),
     password: process.env.VALKEY_PASSWORD,
     url: process.env.VALKEY_URL ?? "redis://localhost:6379",
+    connectTimeout: parseInt(process.env.VALKEY_CONNECT_TIMEOUT_MS ?? "5000", 10),
+    commandTimeout: parseInt(process.env.VALKEY_COMMAND_TIMEOUT_MS ?? "3000", 10),
   },
   claude: {
     apiKey: process.env.CLAUDE_API_KEY,