Deletes port, ncandidates, candidates/master_candidate_t**, vcpus, jobmgr,
workermgr, qmgr, resmgr, xstrings members from cluster_config_t (and their
now-orphaned supporting typedefs) to match the schema shrunk in task 1.1.
Other .c files still referencing these members intentionally do not
compile yet — that's tasks 2.1/2.2/2.3/3.
- Add --vcpus N argp option in main.c; store in myconf.vcpus
- Replace inline argp guard with validate_vcpus() call (returns -EINVAL for <=0)
- Add validate_startup_config() in startup_validation.c: returns 0; writes
deprecation warning into caller-supplied warn_buf when vcpus key present
- Wire validate_startup_config() into myapp_run() after conffile resolved;
emit WARN() if warn_buf non-empty (Req 4.4)
- Remove vcpus field from cluster_config_t (clusterconfig.h)
- Preserve capnp ordinal: vcpus @7 -> vcpusDeprecated @7: Void in controller.capnp
- vtaskmgr_init uses only myconf->vcpus with hardcoded default 8
- Add stub C types in typemap.h for capnp schema extensions from task 1.1
- 96 tests pass
