fix: add overwrite=True to remaining tests that rely on implicit update

Three more test files had write_note calls that create a note then
update it without passing overwrite=True:

- test_obsidian_yaml_formatting.py: test_write_note_update_preserves_yaml_format
- test_tool_json_output_modes.py: test_write_note_text_and_json_modes
- test_tool_write_note_metadata.py: test_metadata_survives_update

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: phernandez <paul@basicmachines.co>

Author: phernandez

tests/mcp/test_obsidian_yaml_formatting.py

@@ -143,6 +143,7 @@ async def test_write_note_update_preserves_yaml_format(app, project_config, test
         directory="test",
         content="Updated content",
         tags=["updated", "new-tag", "format"],
+        overwrite=True,
     )
 
     # Should be an update, not a new creation

tests/mcp/test_tool_json_output_modes.py

@@ -38,6 +38,7 @@ async def test_write_note_text_and_json_modes(app, test_project):
         directory="mode-tests",
         content="# Mode Write Note\n\nupdated",
         output_format="json",
+        overwrite=True,
     )
     assert isinstance(json_result, dict)
     assert json_result["title"] == "Mode Write Note"

tests/mcp/test_tool_write_note_metadata.py

@@ -114,6 +114,7 @@ async def test_metadata_survives_update(app, test_project):
         directory="meta-tests",
         content="# Version 2",
         metadata={"author": "Bob", "version": 2},
+        overwrite=True,
     )
 
     assert "# Updated note" in result