fix(watcher): resolve symlinked .git path before subscribing

[kagura-agent]

Issue for this PR

Closes #26981

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

When .git is a symlink (common with Android's repo tool), the file watcher fails because inotify_add_watch receives the symlink node rather than the underlying directory. inotify rejects this with "Not a directory".

The fix resolves the .git path with realpath before passing it to @parcel/watcher, so inotify always receives the real directory path. Falls back to the original path if realpath fails (e.g. dangling symlink).

How did you verify your code works?

Reproduced the issue by creating a project with a symlinked .git:

mkdir -p /tmp/test/real-git && cd /tmp/test/real-git
git init && echo hi > README.md && git add . && git commit -m init
mkdir /tmp/test/project && cd /tmp/test/project
ln -s ../real-git/.git .git

Confirmed @parcel/watcher (inotify backend) fails on the symlink path and succeeds on the resolved path:

symlink path: FAIL — inotify_add_watch "Not a directory"
realpath:     OK — subscribes successfully

Also ran bun test test/file/ test/config/ — 242 pass, 0 new failures.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[Copilot]

Pull request overview

Fixes Linux/inotify failures when .git is a symlink by resolving the git directory to its real (dereferenced) path before subscribing the file watcher, preventing inotify_add_watch from receiving a symlink node.

Changes:

• Resolve the git dir returned by git rev-parse --git-dir with fs.promises.realpath() before watcher subscription.
• Fall back to the unresolved path when realpath() fails (e.g., dangling symlink).

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[simonklee]

@kagura-agent both issues identified should be addressed

[kagura-agent]

@simonklee Both issues addressed in commit 7f7f4ad:

1. Ignore path mismatch: The condition now checks both the original path (resolved) and the realpath (vcsDir) against cfgIgnores, so user configs that reference the symlink path still work correctly.

2. Symlink regression test: Added a test that creates a real .git directory, moves it to a sibling location, replaces it with a symlink, then verifies the watcher correctly resolves through the symlink and publishes .git/HEAD events from the actual directory. Test is skipped on Windows (no symlink support) and in CI (no native @parcel/watcher binding).

[kagura-agent]

Rebased on latest dev to resolve merge conflict. Adapted symlink test to the new it.instance/TestInstance/AppFileSystem test infrastructure.