fix(apply): reject reserved module names in validate_bundle (parity)

The interactive create path rejects a module whose name shadows a built-in
SDK namespace (`kv`, `secrets`, …) so `import "kv"` can't resolve to a user
module, but `pic apply`'s `validate_bundle` skipped the check — a parity gap
that let a manifest create what the dashboard forbids. Gate it on
`ScriptKind::Module` and share the same `RESERVED_MODULE_NAMES` const (now
`pub(crate)`); endpoints remain unrestricted.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/manager-core/src/api.rs

@@ -260,7 +260,7 @@ async fn create_script<R: ScriptRepository, L: ExecutionLogRepository>(
 /// real KV bridge — defense against author confusion, not a security
 /// boundary (stdlib namespaces and module imports already live in
 /// disjoint Rhai scopes).
-const RESERVED_MODULE_NAMES: &[&str] = &[
+pub(crate) const RESERVED_MODULE_NAMES: &[&str] = &[
     "log",
     "regex",
     "random",