fix(test): serialize web test-runner config swap under a named lock (#3025) (#3373)

The web test runner (vendor/wheels/tests/runner.cfm) swaps the LIVE application.wheels
struct for test configuration (backup in application.$$$wheels) and restores it at the
end of the run. Overlapping test requests clobbered each other's backup, which could
restore TEST config as the live config until the next reload=true, or error the parent
run's restore outright (key [$$$WHEELS] doesn't exist).

Stage-1 slice of the issue-3025 analysis (the titled request-scoped overlay was ruled
infeasible in the 2026-06-22 adversarial analysis):

- Wrap the swap->run->restore window in an exclusive named cflock
  ('wheelsTestRunner_<applicationName>', timeout 1800s, throwOnTimeout), following the
  swap-under-lock precedent in migrator/TenantMigrator.cfc.
- Re-entrancy guard: ParallelRunner partition sub-requests re-enter runner.cfm via fresh
  top-level HTTP GETs while the parent holds the swap. They detect the already-applied
  swap (application.$$$wheels exists) and skip BOTH the swap and the shared lock (a
  unique per-request lock-name suffix), so parallel mode cannot deadlock.
- The restore now runs in a finally block, and only the request that created the backup
  restores it — an erroring suite no longer leaves test config live. No loops in the
  finally block (Lucee 7 miscompiles local-scoped loops in finally).
- Delete the orphaned legacy RocketUnit runner twin vendor/wheels/rocketunit_tests/Test.cfc
  (nothing loads it; the Global.cfc scan-exclusion entry stays). The active CLI/legacy
  chain via wheels.Test and $restoreTestRunnerApplicationScope is untouched.

New spec vendor/wheels/tests/specs/internal/TestRunnerSwapLockSpec.cfc: structural guard
for the lock acquisition + re-entrancy detection, and a behavioral nested-run test that
reproduced the backup clobber before the fix.

Residual gap (intentional, refs #3025): this serializes test-vs-test only. A normal
request concurrent with a test run still reads swapped config; true isolation is
deferred to a separate-application-context design.

Refs #3025

Signed-off-by: Peter Amiri <petera@pai.com>
Co-authored-by: Peter Amiri <petera@pai.com>

Author: bpamiri

changelog.d/test-runner-swap-lock.fixed.md

@@ -0,0 +1,11 @@
+- Web test runner (`/wheels/core/tests` and `/wheels/app/tests`): the swap→run→restore window that
+  temporarily replaces the live `application.wheels` config with test configuration is now serialized
+  under an exclusive named lock, and the restore runs in a `finally` block. Overlapping test requests
+  can no longer clobber each other's `application.$$$wheels` backup and leave test config live until
+  the next `reload=true`, and an erroring suite now restores the original config too. ParallelRunner
+  partition sub-requests detect the already-applied swap and skip both the swap and the shared lock,
+  so parallel test mode does not deadlock. Note: this serializes test-vs-test only — a normal request
+  concurrent with a test run still sees swapped config; true isolation is deferred to a
+  separate-application-context design (refs [#3025](https://github.com/wheels-dev/wheels/issues/3025)).
+  Also removes the orphaned legacy RocketUnit runner twin `vendor/wheels/rocketunit_tests/Test.cfc`
+  (nothing loads it; the active legacy chain via `wheels.Test` is unchanged).