Add new features and tests for AirGap and Time modules

- Introduced `SbomService` tasks documentation.
- Updated `StellaOps.sln` to include new projects: `StellaOps.AirGap.Time` and `StellaOps.AirGap.Importer`.
- Added unit tests for `BundleImportPlanner`, `DsseVerifier`, `ImportValidator`, and other components in the `StellaOps.AirGap.Importer.Tests` namespace.
- Implemented `InMemoryBundleRepositories` for testing bundle catalog and item repositories.
- Created `MerkleRootCalculator`, `RootRotationPolicy`, and `TufMetadataValidator` tests.
- Developed `StalenessCalculator` and `TimeAnchorLoader` tests in the `StellaOps.AirGap.Time.Tests` namespace.
- Added `fetch-sbomservice-deps.sh` script for offline dependency fetching.

src/Findings/StellaOps.Findings.Ledger/StellaOps.Findings.Ledger.csproj

@@ -4,12 +4,19 @@
     <TargetFramework>net10.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
+    <DefaultItemExcludes>$(DefaultItemExcludes);tools/**/*</DefaultItemExcludes>
   </PropertyGroup>
 
   <ItemGroup>
     <None Include="migrations\**\*" Pack="false" CopyToOutputDirectory="Never" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Compile Remove="tools/**/*.cs" />
+    <None Remove="tools/**/*" />
+    <None Include="tools/**/*" Pack="false" CopyToOutputDirectory="Never" />
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.0-rc.2.25502.107" />
     <PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="10.0.0-rc.2.25502.107" />