feat: add .dart_tool to project purge targets and disk analyzer (#179)

cmd/analyze/cleanable.go

@@ -105,6 +105,7 @@ var projectDependencyDirs = map[string]bool{
 	"Pods":        true,
 	".build":      true,
 	"Carthage":    true,
+	".dart_tool":  true,
 
 	// Other tools
 	".terraform": true, // Terraform plugins

cmd/analyze/constants.go

@@ -138,6 +138,7 @@ var foldDirs = map[string]bool{
 	".build":      true,
 	"xcuserdata":  true,
 	"Carthage":    true,
+	".dart_tool":  true,
 
 	// Web frameworks
 	".angular":    true,

lib/clean/project.sh

@@ -21,6 +21,7 @@ readonly PURGE_TARGETS=(
     "obj"           # C# / Unity
     ".turbo"        # Turborepo cache
     ".parcel-cache" # Parcel bundler
+    ".dart_tool"    # Flutter/Dart build cache
 )
 
 # Minimum age in days before considering for cleanup