2026.09.06-e748d6a1e

unix: expose unix.CAP as a name->value lookup table (#392)

Linux capability constants (CAP_NET_ADMIN, ...) were only reachable
as individual named fields, with no way to resolve a name computed
at runtime -- the same gap unix.E/unix.SIG had before #391. Add a
kCapNames NameValue[] array and register it as unix.CAP via the
existing LuaSetNameValueTable helper (not LoadMagnums/MagnumStr,
which only works for OS-resolved extern symbols: CAP_* are
compile-time #define literals with none).

Every existing individual unix.CAP_<NAME> field is untouched.
CAP_LAST_CAP is excluded from the table: it aliases whichever CAP_*
constant is currently highest rather than naming its own capability,
the same shape as SIG's excluded SIG_DFL/SIG_IGN/sigprocmask `how`
values.

definitions.lua annotates unix.CAP as table<string, integer>,
extending the QALLOW_CONSTTYPE and CONST_MAP exceptions #391 already
carries for unix.E/unix.SIG to include it.


Claude-Session: https://claude.ai/code/session_01FfC3JJTfFskaeURnwkLU3o

Co-authored-by: Claude <noreply@anthropic.com>