refactor(elisp): generalize validate-el.sh test-runner for flat layouts

Phase 2 test lookup now triggers for any .el file outside tests/, not
just modules/*.el. Stem-based test matching works the same way; this
just broadens the case pattern.

Before: only modules/foo.el → tests/test-foo*.el triggered Phase 2.
After: foo.el, lib/foo.el, modules/foo.el all do.

init.el and early-init.el are still Phase-1-only (byte-compile would
load the full package graph).

Verified on:
  - emacs.d (modules/-based): modules/browser-config.el still runs
    its matching test, exit 0
  - flat layout (scratch /tmp): source.el at project root successfully
    finds and runs tests/test-source.el

0 files changed, 0 insertions, 0 deletions