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

sampledata/Energiebilanz - Wasser.csv

@@ -0,0 +1,51 @@
+Datum,Zähler Wasser,Wasserverbrauch,€/m³,Kosten,Jahreskosten
+November 2022,820,0,,,
+Dezember 2022,834,14,"5,00 €",70 €,70 €
+Januar 2023,848,14,"5,00 €",70 €,
+Februar 2023,861,13,"5,00 €",65 €,
+März 2023,2,12,"5,00 €",60 €,
+April 2023,15,13,"5,00 €",65 €,
+Mai 2023,50,35,"5,00 €",175 €,
+Juni 2023,75,25,"5,00 €",125 €,
+Juli 2023,93,18,"5,00 €",90 €,
+August 2023,113,20,"5,00 €",100 €,
+September 2023,132,19,"5,00 €",95 €,
+Oktober 2023,144,12,"5,00 €",60 €,
+November 2023,155,11,"5,00 €",55 €,
+Dezember 2023,167,12,"5,00 €",60 €,1.020 €
+Januar 2024,181,14,"5,00 €",70 €,
+Februar 2024,195,14,"5,00 €",70 €,
+März 2024,212,17,"5,00 €",85 €,
+April 2024,251,39,"5,00 €",195 €,
+Mai 2024,266,15,"5,00 €",75 €,
+Juni 2024,297,31,"5,00 €",155 €,
+Juli 2024,312,15,"5,00 €",75 €,
+August 2024,331,19,"5,00 €",95 €,
+September 2024,347,16,"5,00 €",80 €,
+Oktober 2024,360,13,"5,00 €",65 €,
+November 2024,377,17,"5,00 €",85 €,
+Dezember 2024,395,18,"5,00 €",90 €,1.140 €
+Januar 2025,412,17,"5,00 €",85 €,
+Februar 2025,429,17,"5,00 €",85 €,
+März 2025,443,14,"5,00 €",70 €,
+April 2025,458,15,"5,00 €",75 €,
+Mai 2025,475,17,"5,00 €",85 €,
+Juni 2025,511,36,"5,00 €",180 €,
+Juli 2025,529,18,"5,00 €",90 €,
+August 2025,547,18,"5,00 €",90 €,
+September 2025,563,16,"5,00 €",80 €,
+Oktober 2025,580,17,"5,00 €",85 €,
+November 2025,593,13,"5,00 €",65 €,
+Dezember 2025,608,15,"5,00 €",75 €,1.065 €
+Januar 2026,622,14,"7,00 €",98 €,
+Februar 2026,637,15,"7,00 €",105 €,
+März 2026,652,15,"7,00 €",105 €,
+April 2026,671,19,"7,00 €",133 €,
+Mai 2026,687,16,"7,00 €",112 €,
+Juni 2026,,,"7,00 €",0 €,
+Juli 2026,,,"7,00 €",0 €,
+August 2026,,,"7,00 €",0 €,
+September 2026,,,"7,00 €",0 €,
+Oktober 2026,,,"7,00 €",0 €,
+November 2026,,,"7,00 €",0 €,
+Dezember 2026,,,"7,00 €",0 €,