feat: foundation — Docker Compose, OTEL, shared types (P0-002, P0-005, P0-006)

Docker Compose (P0-005):
- PG 17 + pgvector, Valkey 8, OTEL Collector, Jaeger
- OTEL Collector config with trace/metric/log pipelines
- .env.example with all connection strings

OTEL Foundation (P0-006):
- @opentelemetry/sdk-node with auto-instrumentations
- tracing.ts loaded before NestJS bootstrap
- OTLP HTTP exporter → collector → Jaeger
- Disabled fs/dns instrumentations (noisy)

Shared Types (P0-002):
- ChatMessageDto with class-validator (IsUUID, IsNotEmpty, MaxLength)
- ChatResponseDto for REST responses
- Socket.IO typed event maps (ServerToClientEvents, ClientToServerEvents)
- AgentSessionHandle opaque type
- All event payload interfaces shared across gateway/cli/discord

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

packages/types/tsconfig.json

@@ -2,7 +2,9 @@
   "extends": "../../tsconfig.base.json",
   "compilerOptions": {
     "outDir": "dist",
-    "rootDir": "src"
+    "rootDir": "src",
+    "experimentalDecorators": true,
+    "emitDecoratorMetadata": true
   },
   "include": ["src/**/*"],
   "exclude": ["node_modules", "dist"]