feat: add stella-callgraph-node for JavaScript/TypeScript call graph extraction

- Implemented a new tool `stella-callgraph-node` that extracts call graphs from JavaScript/TypeScript projects using Babel AST.
- Added command-line interface with options for JSON output and help.
- Included functionality to analyze project structure, detect functions, and build call graphs.
- Created a package.json file for dependency management.

feat: introduce stella-callgraph-python for Python call graph extraction

- Developed `stella-callgraph-python` to extract call graphs from Python projects using AST analysis.
- Implemented command-line interface with options for JSON output and verbose logging.
- Added framework detection to identify popular web frameworks and their entry points.
- Created an AST analyzer to traverse Python code and extract function definitions and calls.
- Included requirements.txt for project dependencies.

chore: add framework detection for Python projects

- Implemented framework detection logic to identify frameworks like Flask, FastAPI, Django, and others based on project files and import patterns.
- Enhanced the AST analyzer to recognize entry points based on decorators and function definitions.

src/Scanner/__Tests/StellaOps.Scanner.CallGraph.Tests/NodeCallGraphExtractorTests.cs

@@ -0,0 +1,186 @@
+// -----------------------------------------------------------------------------
+// NodeCallGraphExtractorTests.cs
+// Sprint: SPRINT_3610_0003_0001_nodejs_callgraph
+// Description: Unit tests for Node.js/JavaScript call graph extraction.
+// -----------------------------------------------------------------------------
+
+using StellaOps.Scanner.CallGraph.Node;
+using Xunit;
+
+namespace StellaOps.Scanner.CallGraph.Tests;
+
+public class NodeCallGraphExtractorTests
+{
+    [Fact]
+    public void BabelResultParser_ParsesValidJson()
+    {
+        // Arrange
+        var json = """
+        {
+            "module": "my-app",
+            "version": "1.0.0",
+            "nodes": [
+                {
+                    "id": "js:my-app/src/index.handleRequest",
+                    "package": "my-app",
+                    "name": "handleRequest",
+                    "visibility": "public"
+                }
+            ],
+            "edges": [
+                {
+                    "from": "js:my-app/src/index.handleRequest",
+                    "to": "js:external/express.Router",
+                    "kind": "direct"
+                }
+            ],
+            "entrypoints": [
+                {
+                    "id": "js:my-app/src/index.handleRequest",
+                    "type": "http_handler",
+                    "route": "/api/users",
+                    "method": "GET"
+                }
+            ]
+        }
+        """;
+
+        // Act
+        var result = BabelResultParser.Parse(json);
+
+        // Assert
+        Assert.Equal("my-app", result.Module);
+        Assert.Equal("1.0.0", result.Version);
+        Assert.Single(result.Nodes);
+        Assert.Single(result.Edges);
+        Assert.Single(result.Entrypoints);
+    }
+
+    [Fact]
+    public void BabelResultParser_ParsesNodeWithPosition()
+    {
+        // Arrange
+        var json = """
+        {
+            "module": "test",
+            "nodes": [
+                {
+                    "id": "js:test/app.main",
+                    "package": "test",
+                    "name": "main",
+                    "position": {
+                        "file": "app.js",
+                        "line": 10,
+                        "column": 5
+                    }
+                }
+            ],
+            "edges": [],
+            "entrypoints": []
+        }
+        """;
+
+        // Act
+        var result = BabelResultParser.Parse(json);
+
+        // Assert
+        Assert.Single(result.Nodes);
+        var node = result.Nodes[0];
+        Assert.NotNull(node.Position);
+        Assert.Equal("app.js", node.Position.File);
+        Assert.Equal(10, node.Position.Line);
+        Assert.Equal(5, node.Position.Column);
+    }
+
+    [Fact]
+    public void BabelResultParser_ParsesEdgeWithSite()
+    {
+        // Arrange
+        var json = """
+        {
+            "module": "test",
+            "nodes": [],
+            "edges": [
+                {
+                    "from": "js:test/a.foo",
+                    "to": "js:test/b.bar",
+                    "kind": "callback",
+                    "site": {
+                        "file": "a.js",
+                        "line": 25
+                    }
+                }
+            ],
+            "entrypoints": []
+        }
+        """;
+
+        // Act
+        var result = BabelResultParser.Parse(json);
+
+        // Assert
+        Assert.Single(result.Edges);
+        var edge = result.Edges[0];
+        Assert.Equal("callback", edge.Kind);
+        Assert.NotNull(edge.Site);
+        Assert.Equal("a.js", edge.Site.File);
+        Assert.Equal(25, edge.Site.Line);
+    }
+
+    [Fact]
+    public void BabelResultParser_ThrowsOnEmptyInput()
+    {
+        // Arrange & Act & Assert
+        Assert.Throws<ArgumentException>(() => BabelResultParser.Parse(""));
+        Assert.Throws<ArgumentException>(() => BabelResultParser.Parse(null!));
+    }
+
+    [Fact]
+    public void BabelResultParser_ParsesNdjson()
+    {
+        // Arrange
+        var ndjson = """
+        {"type": "progress", "percent": 50}
+        {"type": "progress", "percent": 100}
+        {"module": "app", "nodes": [], "edges": [], "entrypoints": []}
+        """;
+
+        // Act
+        var result = BabelResultParser.ParseNdjson(ndjson);
+
+        // Assert
+        Assert.Equal("app", result.Module);
+    }
+
+    [Fact]
+    public void JsEntrypointInfo_HasCorrectProperties()
+    {
+        // Arrange
+        var json = """
+        {
+            "module": "api",
+            "nodes": [],
+            "edges": [],
+            "entrypoints": [
+                {
+                    "id": "js:api/routes.getUsers",
+                    "type": "http_handler",
+                    "route": "/users/:id",
+                    "method": "GET"
+                }
+            ]
+        }
+        """;
+
+        // Act
+        var result = BabelResultParser.Parse(json);
+
+        // Assert
+        Assert.Single(result.Entrypoints);
+        var ep = result.Entrypoints[0];
+        Assert.Equal("js:api/routes.getUsers", ep.Id);
+        Assert.Equal("http_handler", ep.Type);
+        Assert.Equal("/users/:id", ep.Route);
+        Assert.Equal("GET", ep.Method);
+    }
+}