fix(app): normalize Windows paths for consistent project matching

[Rettend]

What does this PR do?

fixes #11666, see issue description.

How did you verify your code works?

1. open a project with ctrl+o
2. open the same project with the opencode deep link
   -> only one project is open

Admittedly the scope of these changes is larger, and I am not sure this is the best way to fix the issue.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on the search results, I found several related PRs that address similar Windows path handling and project matching issues:

Potentially Related PRs:

1. PR fix: use case-insensitive path comparison on Windows to prevent duplicate projects #6626 - "fix: use case-insensitive path comparison on Windows to prevent duplicate projects"

   • Directly addresses preventing duplicate projects on Windows, which aligns with the issue being fixed

2. PR fix(lsp): normalize Windows drive letter case for consistent URIs #10049 - "fix(lsp): normalize Windows drive letter case for consistent URIs"

   • Similar path normalization approach for Windows

3. PR fix(windows): path handling fixes for Windows #6763 - "fix(windows): path handling fixes for Windows"

   • General Windows path handling fixes

4. PR fix(app): allow browsing absolute paths on Windows #6624 - "fix(app): allow browsing absolute paths on Windows"

   • Related to Windows path handling

Why they're related:
These PRs address the same core issue - Windows path handling inconsistencies that can lead to duplicate project detection. PR #6626 specifically focuses on preventing duplicate projects through case-insensitive comparison, which is directly related to the current PR's goal of normalizing paths for consistent project matching when using deep links vs. manual project opening.