test(worker): add unit tests for php and swift workers

Extract testable logic from exec.mjs into lib.mjs (preprocessCode,
createIOCallbacks, buildResult) and add vitest tests. Add Go tests
for models, exec helpers, and handlers in worker/swift. Update
justfiles to include test tasks for local dev and CI.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/worker/php/justfile b/worker/php/justfile
index 115165d..896798b 100644
--- a/worker/php/justfile
+++ b/worker/php/justfile
@@ -1,5 +1,9 @@
 check:
     npm run check
 
+test:
+    npm test
+
 ci:
     npx biome ci .
+    npm test