feat: production readiness pass

[austinchima]

What this PR does

Implements a full production-readiness pass across all layers of the application.

Changes

• Serilog — Replaced default Microsoft logger with structured logging. Console sink (dev) + rolling daily file sink with 7-day retention. Bootstrap logger catches startup crashes. One structured event per HTTP request via UseSerilogRequestLogging.
• BenchmarkDotNet — New MySupplyChain.Benchmarks project with 4 benchmark classes covering SSA forecasting, CQRS command handlers, query handlers, and CSV parsing of the 913K-row dataset.
• Real dataset — Trained 50 per-product SSA models on the Kaggle Store Item Demand Forecasting dataset (913,000 rows). Moved dataset to data/ directory.
• Dead code removed — Deleted orphaned ModelInput, ModelOutput, DataGenerator, TestDataGenerator classes that referenced a regression model that was never built.
• Docker — Added Dockerfile, docker-compose.yml, and .dockerignore.
• CI — Added GitHub Actions pipeline targeting main.
• .NET 10 — Upgraded all 6 projects from .NET 9 to .NET 10.
• Solution cleanup — Removed phantom root-level MySupplyChain.csproj from solution.

Testing

• dotnet build — 0 warnings, 0 errors across all 7 projects
• dotnet test — all tests passing

[gitguardian]

️✅ There are no secrets present in this pull request anymore.

If these secrets were true positive and are still valid, we highly recommend you to revoke them.
While these secrets were previously flagged, we no longer have a reference to the
specific commits where they were detected. Once a secret has been leaked into a git
repository, you should consider it compromised, even if it was deleted immediately.
Find here more information about risks.

---

^{_{🦉 GitGuardian detects secrets in your source code to help developers and security teams secure the modern development process. You are seeing this because you or someone else with access to this repository has authorized GitGuardian to scan your pull request.}}