[Code Origin] DEBUG-4174 - Make Code Origin on by default (#8272)

## Summary of changes
Enable Code Origin for entry spans by default
(DD_CODE_ORIGIN_FOR_SPANS_ENABLED now defaults to true).

Add the always-present Code Origin tags as generated tag properties on
AspNetCoreTags

Update ASP.NET Core integration snapshots and metadata rules to account
for Code Origin tags on entry spans.

## Reason for change
Make Code Origin tags available out-of-the-box on supported entry spans
(currently ASP.NET Core).

## Implementation details
`CodeOriginForSpansEnabled` now uses `WithDefault(true)`.
Explicit `DD_CODE_ORIGIN_FOR_SPANS_ENABLED=false` still hard-disables.

Reduce allocations/locking on the entry-span hot path by leveraging
generated tag properties for Code Origin fields.
- `AspNetCoreTags` and `AspNetCoreSingleSpanTags` add generated `[Tag]`
properties for entry Code Origin tags, scoped to ASP.NET Core entry
spans.
- Code Origin tags are only emitted when set.
- Unsupported tag types are skipped with a debug log instead of using
the generic `ITags` write path.
- Code Origin presence checks use the concrete ASP.NET Core tag
properties first, then fall back to generic tag lookup for duplicate
detection.

## Test coverage
Updated focused unit coverage:
- `Datadog.Trace.Tests.Debugger.SpanCodeOriginTests`
- `Datadog.Trace.Tests.Debugger.DebuggerSettingsTests`
-
`Datadog.Trace.Tests.DiagnosticListeners.AspNetCoreDiagnosticObserverTests`
- `Datadog.Trace.Debugger.IntegrationTests.DebuggerManagerTests`
- `Datadog.Trace.Debugger.IntegrationTests.DebuggerManagerDynamicTests`

Updated ASP.NET Core integration snapshots to verify serialized Code
Origin tags across affected APM, Security, IAST, MVC, minimal API, and
IIS scenarios.

Added Verify scrubbers/tests for Code Origin file paths, line numbers,
and column numbers so snapshot output is stable across machines.

Author: dudikeleti

docs/span_attribute_schema/v0.md

@@ -241,6 +241,9 @@ public void ParseRequirements(ArgumentListSyntax arg, PropertyType propertyType)
                         case "IsPresent": // only for tags
                             requiredValue = "Yes";
                             break;
+                        case "IsAbsent": // only for tags - must NOT be present
+                            requiredValue = "Must be absent";
+                            break;
                         case "PassesThroughSource": // only for additional tags
                             operationName = "PassThru";
                             requiredValue = "No";

docs/span_attribute_schema/v1.md

@@ -119,6 +119,10 @@ public record TrimmingScenario : SmokeTestScenario
     public required string PackageName { get; init; }
     public string? PackageVersionSuffix { get; init; }
     public string InstallCommand => InstallType.GetInstallCommand();
+
+    // Single-file trimming publishes bundled user assemblies without Assembly.Location.
+    // Code Origin still emits reflection-derived frame tags, but PDB-backed file/line/column tags are unavailable.
+    public override string SnapshotFile => "smoke_test_snapshots_trimming";
 }
 
 public record WindowsMsiScenario : SmokeTestScenario

tracer/build/_build/GenerateSpanDocumentation/Program.cs

@@ -9,7 +9,7 @@ WORKDIR /src
 COPY ./test/test-applications/regression/AspNetCoreSmokeTest/ .
 
 ARG PUBLISH_FRAMEWORK
-RUN dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% -o /src/publish
+RUN dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% /p:PathMap=C:\src=/src -o /src/publish
 
 FROM $RUNTIME_IMAGE AS publish-msi
 SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]

tracer/build/_build/SmokeTests/SmokeTestScenario.cs

@@ -9,7 +9,7 @@ WORKDIR /src
 COPY ./test/test-applications/regression/AspNetCoreSmokeTest/ .
 
 ARG PUBLISH_FRAMEWORK
-RUN dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% -o /src/publish
+RUN dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% /p:PathMap=C:\src=/src -o /src/publish
 
 FROM $RUNTIME_IMAGE AS publish-msi
 SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]

tracer/build/_build/docker/smoke.windows.dd-dotnet.dockerfile

@@ -9,7 +9,7 @@ WORKDIR /src
 COPY ./test/test-applications/regression/AspNetCoreSmokeTest/ .
 
 ARG PUBLISH_FRAMEWORK
-RUN dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% -o /src/publish
+RUN dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% /p:PathMap=C:\src=/src -o /src/publish
 
 FROM $RUNTIME_IMAGE AS publish
 SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]

tracer/build/_build/docker/smoke.windows.dockerfile

@@ -9,7 +9,7 @@ WORKDIR /src
 COPY ./test/test-applications/regression/AspNetCoreSmokeTest/ .
 
 ARG PUBLISH_FRAMEWORK
-RUN dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% -o /src/publish
+RUN dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% /p:PathMap=C:\src=/src -o /src/publish
 
 FROM $RUNTIME_IMAGE AS publish
 SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]

tracer/build/_build/docker/smoke.windows.dotnet-tool.dockerfile

@@ -9,7 +9,7 @@ WORKDIR /src
 COPY ./test/test-applications/regression/AspNetCoreSmokeTest/ .
 
 ARG PUBLISH_FRAMEWORK
-RUN dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% -o /src/publish
+RUN dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% /p:PathMap=C:\src=/src -o /src/publish
 
 FROM $RUNTIME_IMAGE AS publish
 SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]

tracer/build/_build/docker/smoke.windows.fleet-installer.dockerfile

@@ -16,7 +16,7 @@ ARG TOOL_VERSION
 RUN dotnet restore "AspNetCoreSmokeTest.csproj" \
     && dotnet nuget add source "c:\src\artifacts" \
     && dotnet add package "Datadog.Trace.Bundle" --version %TOOL_VERSION% \
-    && dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% -o "c:\src\publish"
+    && dotnet publish "AspNetCoreSmokeTest.csproj" -c Release --framework %PUBLISH_FRAMEWORK% /p:PathMap=C:\src=/src -o "c:\src\publish"
 
 FROM $RUNTIME_IMAGE AS publish-msi
 SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]