M0: scaffold solution, EF+Timescale schema, /healthz

Five-project Clean Architecture solution (Core/Infrastructure/App + Core.Tests/
Integration.Tests) on .NET 10 with central package management, snake_case EF mapping,
and shared build/style config.

- Full domain entity set + EF DbContext for the SDD §5.3 schema (singular table names).
- InitialSchema migration (relational) + TimescaleHypertables migration (raw SQL:
  create_hypertable + compression on reading, hypertable on consumption).
- App wiring: Serilog (actually wired, unlike MQTTower), DbContext, migrate-on-startup,
  /healthz. Serves plain HTTP behind a reverse proxy (no HTTPS redirect).
- deploy/Dockerfile (2-stage, ICU-capable) + docker-compose (app + timescaledb).
- Integration.Tests: shared TimescaleFixture (Testcontainers) — migrations, hypertables,
  compression policy, and /healthz all verified green (4/4).

Claude-Session: https://claude.ai/code/session_01WujdMtMJPbxDpDnMeK22rr

.gitignore

@@ -0,0 +1,46 @@
+# .NET build output
+bin/
+obj/
+[Dd]ebug/
+[Rr]elease/
+x64/
+x86/
+[Aa][Rr][Mm]/
+[Aa][Rr][Mm]64/
+artifacts/
+publish/
+*.user
+*.userosscache
+*.suo
+*.dll
+*.exe
+*.pdb
+
+# Rider / VS / VS Code
+.idea/
+.vs/
+*.sln.iml
+
+# Test / coverage
+[Tt]est[Rr]esult*/
+coverage*.json
+coverage*.xml
+coverage*.cobertura.xml
+*.trx
+
+# NuGet
+*.nupkg
+*.snupkg
+.nuget/
+packages/
+
+# Environment / secrets (never commit)
+.env
+.env.*
+*.env
+appsettings.*.Local.json
+secrets.json
+
+# OS
+.DS_Store
+Thumbs.db