Fix Serilog misconfiguration: silence, unstructured logs, and missing File sink

[Copilot]

Three Serilog misconfigurations in Program.cs caused all Information-level startup logs to be silenced, produced unstructured log output, and left no persistent log trail.

Changes

• MinimumLevel: Warning → Information — allows startup Log.Information(...) calls to emit
• File sink: Added rolling daily file sink via Serilog.Sinks.File v6.0.0 for persistent log retention
• Structured logging: Fixed interpolated string to use a named message template property

// Before
.MinimumLevel.Warning()
.WriteTo.Console()
// ...
Log.Information($"Using SQLite database at: {sqlitePath}");

// After
.MinimumLevel.Information()
.WriteTo.Console()
.WriteTo.File("logs/mythapi-.log", rollingInterval: RollingInterval.Day)
// ...
Log.Information("Using SQLite database at: {SqlitePath}", sqlitePath);

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Bug] Serilog misconfiguration in Program.cs silences logs and breaks structured logging</issue_title>
<issue_description>## Description
The Serilog configuration in Program.cs has three critical issues that cause log entries to be silenced and violate structured logging best practices.

Issue 1: MinimumLevel set to Warning swallows all Information logs

MinimumLevel.Warning() is configured, meaning all Log.Information(...) calls scattered throughout Program.cs are never emitted — including startup messages, database selection info, and schema creation confirmations.

Issue 2: String interpolation instead of structured logging templates

Several log calls use C# string interpolation ($"...") instead of Serilog's message templates, which defeats structured logging and breaks log querying:

// ❌ Current — plain string, no structured properties
Log.Information($"Using SQLite database at: {sqlitePath}");

// ✅ Expected — structured template with named property
Log.Information("Using SQLite database at: {SqlitePath}", sqlitePath);

Issue 3: Only the Console sink is configured

No secondary/persistent sink (e.g. File) is configured, meaning all logs are lost after a process restart. The org logging guidelines recommend at least a File sink for non-development environments.

Steps to Reproduce

1. Run the application with ASPNETCORE_ENVIRONMENT=Development
2. Observe no Information-level startup messages appear in the console output

Expected Behavior

• All Log.Information(...) calls in Program.cs emit to the console
• Log messages use structured templates (e.g. "Using SQLite database at: {SqlitePath}")
• A File sink is configured for persistent log retention

Actual Behavior

• MinimumLevel.Warning() silences all Information log entries
• Interpolated strings produce unstructured log messages
• Logs are console-only and lost on restart

Environment

• .NET 8.0
• Serilog (ASP.NET Core integration via builder.Host.UseSerilog())

Proposed Fix

In Program.cs:

Log.Logger = new LoggerConfiguration()
    .Enrich.FromLogContext()
    .Enrich.WithProperty("Application", "MythApi")
    .Enrich.WithProperty("Environment", Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT") ?? "Production")
    .MinimumLevel.Information()                          // ✅ Allow Information logs
    .WriteTo.Console()
    .WriteTo.File("logs/mythapi-.log", rollingInterval: RollingInterval.Day)  // ✅ Add File sink
    .CreateLogger();

Fix interpolated calls:

// Before
Log.Information($"Using SQLite database at: {sqlitePath}");

// After
Log.Information("Using SQLite database at: {SqlitePath}", sqlitePath);

Acceptance Criteria

• MinimumLevel changed from Warning to Information
• All Log.Information($"...") calls converted to structured message templates
• A rolling File sink added to the Serilog configuration
• All existing Log.Information startup messages are visible in console output when running the application
  </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Bug] Serilog misconfiguration in Program.cs silences logs and breaks structured logging #30

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