refactor(src): Phase 10.2 batch 2 - outline_tool Result[T] migration

Migrates 3 sites in src/outline_tool.py:
1. L49 (outline body) - the ast.parse SyntaxError handler.
   outline() now returns Result[str]. On SyntaxError, the data
   is the formatted error string (preserved for backwards-compat
   with callers that read the formatted string), and the errors
   list has the ErrorInfo.
2. L90 (walk ast.unparse for returns) - was except ...: pass.
   Now appends ErrorInfo to enclosing parse_errors list.
3. L109 (walk ast.unparse for ImGui context) - same.

outline() returns Result(data='\n'.join(output), errors=parse_errors).
get_outline() also returns Result[str].

Tests updated to check result.ok and use result.data.

tests/test_outline_tool.py

@@ -8,14 +8,15 @@ def test_code_outliner_type_hints():
 class Test:
     def my_method(self, x: int) -> str:
         return "hello"
-        
+
 def my_func(a: bool) -> None:
     pass
 """
     outliner = CodeOutliner()
     result = outliner.outline(code)
-    assert "[Method] my_method -> str (Lines 3-4)" in result
-    assert "[Func] my_func -> None (Lines 6-7)" in result
+    assert result.ok, f"outline failed: {result.errors}"
+    assert "[Method] my_method -> str (Lines 3-4)" in result.data
+    assert "[Func] my_func -> None (Lines 6-7)" in result.data
 
 def test_code_outliner_imgui_scopes():
     code = """
@@ -27,8 +28,9 @@ def render_gui() -> None:
 """
     outliner = CodeOutliner()
     result = outliner.outline(code)
-    assert "[ImGui Scope] imscope.window('My Window') (Lines 3-6)" in result
-    assert "[ImGui Scope] imscope.child('My Child') (Lines 5-6)" in result
+    assert result.ok, f"outline failed: {result.errors}"
+    assert "[ImGui Scope] imscope.window('My Window') (Lines 3-6)" in result.data
+    assert "[ImGui Scope] imscope.child('My Child') (Lines 5-6)" in result.data
 
 def test_code_outliner_nested_ifs():
     code = """
@@ -39,4 +41,5 @@ def render_gui() -> None:
 """
     outliner = CodeOutliner()
     result = outliner.outline(code)
-    assert "[ImGui Scope] imscope.window('My Window') (Lines 4-5)" in result
+    assert result.ok, f"outline failed: {result.errors}"
+    assert "[ImGui Scope] imscope.window('My Window') (Lines 4-5)" in result.data