[5.x] Make time-based sharding namespace-agnostic and forward --test-directory (#1677)

* refactor(shard): extract parseListTestsOutput for testability

* test(shard): characterize parseListTestsOutput current behavior

* fix(shard): parse any PHP FQCN namespace from --list-tests

* fix(shard): forward --test-directory to list-tests subprocess

* chore: lint + snapshot fixups

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* refactor(shard): make extracted helpers private, test via reflection

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* revert visual_snapshot_of_help_command_output

* revert visual_snapshot_of_help_command_output

* keep function removeParallelArguments

* strip --processes argument when building list-tests command

The removeParallelArguments method was not filtering --processes flags, causing the list-tests subprocess to fail when parallel execution was enabled. This prevented time-based sharding from working correctly with the --parallel option.

Now both --parallel/-p and --processes arguments are removed from the command used to enumerate tests, ensuring the subprocess runs successfully.

* test: re-add namespace-agnostic sharding tests

- 5.x merge kept describe()-style test file, dropped PR #1677 tests for parseListTestsOutput + buildListTestsCommand. Re-add them in matching style.
- Also fix removeParallelArguments test broken by merge: source array_values() + strips --processes, so expects ['bin/pest','tests/'].

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/.snapshots/success.txt

@@ -1983,4 +1983,4 @@
   ✓ pass with dataset with ('my-datas-set-value')
   ✓ within describe → pass with dataset with ('my-datas-set-value')
 
-  Tests:    2 deprecated, 4 warnings, 5 incomplete, 2 notices, 40 todos, 35 skipped, 1370 passed (3068 assertions)
+  Tests:    2 deprecated, 4 warnings, 5 incomplete, 2 notices, 40 todos, 35 skipped, 1370 passed (3068 assertions)