Add PHP Analyzer Plugin and Composer Lock Data Handling

- Implemented the PhpAnalyzerPlugin to analyze PHP projects.
- Created ComposerLockData class to represent data from composer.lock files.
- Developed ComposerLockReader to load and parse composer.lock files asynchronously.
- Introduced ComposerPackage class to encapsulate package details.
- Added PhpPackage class to represent PHP packages with metadata and evidence.
- Implemented PhpPackageCollector to gather packages from ComposerLockData.
- Created PhpLanguageAnalyzer to perform analysis and emit results.
- Added capability signals for known PHP frameworks and CMS.
- Developed unit tests for the PHP language analyzer and its components.
- Included sample composer.lock and expected output for testing.
- Updated project files for the new PHP analyzer library and tests.

src/Graph/__Tests/StellaOps.Graph.Indexer.Tests/GraphAnalyticsPipelineTests.cs

@@ -0,0 +1,32 @@
+using System.Collections.Immutable;
+using Microsoft.Extensions.Logging.Abstractions;
+using StellaOps.Graph.Indexer.Analytics;
+
+namespace StellaOps.Graph.Indexer.Tests;
+
+public sealed class GraphAnalyticsPipelineTests
+{
+    [Fact]
+    public async Task RunAsync_WritesClustersAndCentrality()
+    {
+        var snapshot = GraphAnalyticsTestData.CreateLinearSnapshot();
+
+        var provider = new InMemoryGraphSnapshotProvider();
+        provider.Enqueue(snapshot);
+
+        using var metrics = new GraphAnalyticsMetrics();
+        var writer = new InMemoryGraphAnalyticsWriter();
+        var pipeline = new GraphAnalyticsPipeline(
+            new GraphAnalyticsEngine(new GraphAnalyticsOptions()),
+            provider,
+            writer,
+            metrics,
+            NullLogger<GraphAnalyticsPipeline>.Instance);
+
+        await pipeline.RunAsync(new GraphAnalyticsRunContext(false), CancellationToken.None);
+
+        Assert.Single(writer.ClusterWrites);
+        Assert.Single(writer.CentralityWrites);
+        Assert.Equal(snapshot.Nodes.Length, writer.ClusterWrites.Single().Assignments.Length);
+    }
+}