feat: V2 microservices stack — backend services, gateway, JWT auth

Add full V2 architecture: identity, content, studio (.NET 10) and file,
render, notification, gateway (Go) services with vendored deps, plus DB
migrations, event/API contracts, and an init-db script.

Wire the Next.js frontend to the gateway: server-side JWT auth routes
(login/register/refresh/logout/me), gateway fetch helper, and session/
cookie/jwt helpers under src/lib.

Containerize the stack via docker-compose.v2.yml and per-service
Dockerfiles. Base images resolve through a Nexus mirror (Docker Hub) and
MCR directly; npm/NuGet pull from Nexus groups. Self-host fonts via
next/font/local to avoid Google Fonts (geo-blocked).

Add CI workflow and ignore .env.v2, *.stackdump, and .NET bin/obj.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

services/render/vendor/github.com/modern-go/reflect2/.travis.yml

@@ -0,0 +1,15 @@
+language: go
+
+go:
+  - 1.9.x
+  - 1.x
+
+before_install:
+  - go get -t -v ./...
+  - go get -t -v github.com/modern-go/reflect2-tests/...
+
+script:
+  - ./test.sh
+
+after_success:
+  - bash <(curl -s https://codecov.io/bash)