feat(test): chrome-use test <suite.yaml> — re-runnable browser test suites

Turn repetitive browser checks into unit-test-style YAML suites. Steps reuse
chrome-use's own commands; assertions (url/visible/hidden/text/count/eval)
compile to a single truthy `eval`. The runner re-invokes the binary per step
(inherits all flag/launch/daemon/ref semantics; the daemon stays up so each
step is a fast socket call), launches an isolated browser by default, captures a
screenshot on failure, and exits non-zero for CI. `setup: account:` injects a
cookie-use login. Ships a `test` skill (skills get test). Unit-tested step/assert
compilation.

.gitignore

@@ -75,3 +75,4 @@ out/
 # extension signing key (never commit) + local-only id record
 .secrets/
 *.pem
+/cu-test-artifacts