patch_content breaks Markdown structure when modifying heading sections

[7shi]

When using patch_content with any operation (append, prepend, or replace) to modify a heading section, it doesn't add necessary line breaks, which breaks the Markdown structure.

Example:

When applying:

{
  operation: "append",
  target_type: "heading",
  target: "test1",
  content: "baz"
}

to:

# test1
foo
# test2
bar

Current output:

# test1
foo
baz# test2
bar

Expected output:

# test1
foo
baz
# test2
bar

The function should automatically handle line breaks to preserve Markdown formatting for all operations.

[MarkusPfundstein]

We need to check what the API expects here and what is the behaviour of the API.

[7shi]

Yes, I agree. That's why I avoided creating a PR independently and raised this as an issue first.

[7shi]

For additional context:

While testing mcp-obsidian, some users suggested that direct access to the Vault via the MCP filesystem server would be sufficient, eliminating the need for a specialized solution. I thought the main advantage of mcp-obsidian might be limited to specific functionalities like partial page modifications (e.g., appending content to specific headings).

However, this patch_content has been unstable due to issues with both the REST API and MCP, as evidenced by my previous PRs.