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/go-ini/ini/.golangci.yml

@@ -0,0 +1,27 @@
+linters-settings:
+  staticcheck:
+    checks: [
+      "all",
+      "-SA1019" # There are valid use cases of strings.Title
+    ]
+  nakedret:
+    max-func-lines: 0 # Disallow any unnamed return statement
+
+linters:
+  enable:
+    - deadcode
+    - errcheck
+    - gosimple
+    - govet
+    - ineffassign
+    - staticcheck
+    - structcheck
+    - typecheck
+    - unused
+    - varcheck
+    - nakedret
+    - gofmt
+    - rowserrcheck
+    - unconvert
+    - goimports
+    - unparam