…ectory to avoid evaluation order issues

- Changed from baseDirectory.getParentFile/spark to (delta-spark-v1/baseDirectory).value
- This is more explicit and clearly shows we're using delta-spark-v1's directory
- Makes the relationship between modules more obvious

Issue: Test resource directories were using baseDirectory.getParentFile/spark
which could evaluate to the wrong path depending on evaluation order.

Solution: Changed all test path configurations to consistently use
(delta-spark-v1/baseDirectory).value:
- Test/unmanagedSourceDirectories
- Test/unmanagedResourceDirectories
- Test/resourceDirectory
- Test/baseDirectory
- Test/javaOptions (-Duser.dir)

This ensures all test paths correctly point to the spark/ directory
regardless of evaluation order, fixing GitHub Actions failures.

…ions issue

…ectory

Root cause: TestParallelization.defaultForkOptions was using baseDirectory.value
for workingDirectory, but spark module's Test/baseDirectory points to spark/
while baseDirectory points to spark-combined/.

When GitHub Actions runs 'spark/test' with TEST_PARALLELISM_COUNT=4 SHARD_ID=x,
the forked test JVMs got spark-combined/ as working directory, causing tests
that use relative paths (like 'src/test/resources/delta/table-with-dv-large')
to fail.

Solution: Changed defaultForkOptions to use (Test/baseDirectory).value instead
of baseDirectory.value, so it correctly uses spark/ as the working directory.

This only affects the spark module which is the only user of TestParallelization.

Issue: serverClassPath contains multiple 'classes' directories with the same name
(e.g., spark/target/scala-2.12/classes, storage/target/scala-2.12/classes, etc.).
When creating symlinks, the code tried to create multiple symlinks all named 'classes',
causing FileAlreadyExistsException.

Solution: Track created symlink names in a Set and skip duplicates. Only the first
occurrence of each filename will have a symlink created.

Also added Files.exists() check and similar fix for log4j properties symlink.

The issue is simply that serverClassPath contains multiple directories with
the same name (e.g., 7 different 'classes' directories). Using a Set to track
created symlink names is sufficient - no need for try-catch or concurrent
access handling since each shard runs in its own workspace.

Changed kernelDefaults to depend on local delta-spark-v1 instead of
published delta-spark 3.3.2. This makes the dependency consistent with
goldenTables (which already uses delta-spark-v1) and allows testing
against the current codebase.

Changes:
- Added .dependsOn(`delta-spark-v1` % "test") to kernelDefaults
- Removed external 'io.delta' %% 'delta-spark' % '3.3.2' % 'test' dependency