Allow customization of title to include link to folder level above

Bug description

I have a blog that has the following directory structure:

$ tree
.
├── 404.qmd
├── _quarto.qmd
├── blog
│  ├── index.qmd
│  ├── welcome-to-my-blog
│  │  └── index.qmd
│  └── writing-papers-with-markdown
│     └── index.qmd
└── index.qmd

When visiting the page for welcome-to-my-blog, there's current no way for a user to go back up just one level:

It is possible for users to click on the logo icon to go to the home level though.

It would be nice if this could be made to be like this instead:

where ~ was clickable to get to the root level and blog was clickable to blog folder level. Ideally it would be customizable with what text we'd want to show there. You wouldn't need to add / like I have in the screenshot, users can probably customize that with css before and after selectors. Users can always hide this by setting display: none.

What are your thoughts?

I'm using title: false in the navbar but adding a link to the logo in the _quarto.yml for the screenshots above:

website:
  title: "kdheepak"
  favicon: ./_quarto/favicon.svg
  search:
    location: navbar
  site-url: https://kdheepak.com
  repo-url: https://github.com/kdheepak/kdheepak.github.io
  repo-actions: [edit, issue]
  open-graph: true
  twitter-card: true
  sidebar:
    alignment: left
    style: docked
  navbar:
    title: false
    logo: _quarto/favicon.svg
    collapse: false
    search: true
    pinned: false
    right:
      - icon: github
        href: https://github.com/kdheepak
        aria-label: GitHub
      - icon: rss
        href: index.xml
        aria-label: RSS

Checklist

• Please include a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
• Please format your issue so it is easier for us to read the bug report.
• Please document the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
• Please document the operating system you're running. If on Linux, please provide the specific distribution.
• Please provide the output of quarto check so we know which version of quarto and its dependencies you're running.

Start with the navbar configuration in _quarto.yml, especially title, logo, and sidebar behavior, and trace how page paths are represented for nested .qmd content. Done means nested pages expose clickable links for each parent folder, with configurable displayed text and behavior that preserves existing title and logo options.