Replaces the hint resolver's signature-matching (does the expected set
contain all five literal forms? an Ident{NewName}?) with a grammar-
declared annotation. New Node::Hinted { mode, inner } wrapper; the
walker records the mode in WalkContext::pending_hint_mode on entry and
clears it on any successful match (cursor moved past the slot — this
also undoes the leak where a failed Hinted branch of a Choice would
otherwise strand a stale mode). The resolver reads pending_hint_mode
directly.
Value-literal fallback slots carry ProseOnly; NewName ident slots carry
ForceProse. hint_mode_at_input_inner now delegates to
hint_resolution_at_input — one resolution path, no duplicated logic.
No behaviour change; the typing-surface matrix guards it.
claude@clouddev1
911a537a83