fix(scan): Normalize project path to absolute before building callgraph

Fixed critical bug where scan command failed to index any functions in the
callgraph when using relative paths (e.g., --project .).

Root Cause:
- graph.Initialize() created nodes with relative file paths
- BuildModuleRegistry() converted paths to absolute internally
- indexFunctions() couldn't match relative paths to absolute paths
- All functions skipped, resulting in 0 vulnerabilities detected

Solution:
Convert projectPath to absolute using filepath.Abs() before passing to
both graph.Initialize() and callgraph.BuildCallGraph() to ensure
consistent path representation throughout the pipeline.

Impact:
- Before: "indexed 0, skipped_registry=1149" (0 functions)
- After: "indexed 1149, skipped_registry=0" (all functions)
- Integration test now correctly detects vulnerabilities

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: shivasurya

sourcecode-parser/cmd/scan.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"path/filepath"
 
 	"github.com/shivasurya/code-pathfinder/sourcecode-parser/dsl"
 	"github.com/shivasurya/code-pathfinder/sourcecode-parser/graph"
@@ -34,6 +35,13 @@ Examples:
 			return fmt.Errorf("--project flag is required")
 		}
 
+		// Convert project path to absolute path to ensure consistency
+		absProjectPath, err := filepath.Abs(projectPath)
+		if err != nil {
+			return fmt.Errorf("failed to resolve project path: %w", err)
+		}
+		projectPath = absProjectPath
+
 		// Step 1: Build code graph (AST)
 		log.Printf("Building code graph from %s...\n", projectPath)
 		codeGraph := graph.Initialize(projectPath)