Initial commit: Keycloak SSO for MischLabs

Keycloak 26.1 + PostgreSQL 16 Docker stack with pre-configured
realm containing 10 OIDC clients for all MischLabs services.
Includes integration guides for Tier 1-3 services.

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

.gitignore

@@ -0,0 +1,19 @@
+# Secrets
+.env
+
+# PostgreSQL data
+pgdata/
+
+# OS files
+.DS_Store
+Thumbs.db
+*.swp
+*.swo
+*~
+
+# IDE
+.vscode/
+.idea/
+
+# Claude Code
+.claude/