resolver: accept angle-bracket applied types (Option<Char>) in value/return position #131

Part of #128.

Resolver accepts <...> for type parameters but rejects it for applied types in value/return position (e.g. fn char_at(...) -> Option<Char>). This asymmetry is the core defect behind #128; it blocks the entire stdlib (option.affine 36 uses, result.affine 24, collections.affine 22, …), not just string.affine.

Task: make the resolver accept angle-bracket applied types in value/return/let position, equivalent to the bracket form (Option[Char]). This is the preferred path from #128 — it makes the existing stdlib compile unchanged and is consistent with the <...> parameter syntax already accepted.

Done when: Option<Char>, Result<T,E>, [Option<T>] etc. resolve in applied position; existing bracket-form tests still pass; a focused resolver test covers applied-angle types.

Unblocks: #128-E, #128-H.