(GT-K03318): Don't map to U+81FD; add `ideographic-structure'; add

(GT-K03318): Don't map to U+81FD; add `ideographic-structure'; add
`<-simplified@component' for U+81FD.
(GT-K03616): Likewise.
(U+668E): Use `->denotational' and `->subsumptive'.
(U+66C2): Use `->denotational'.
(U+66C3): Use `->denotational'.
(U+66C4): Use `->denotational'.
(U+66C5): Use `->denotational'; add `sound@ja/on'.
(U+66C6): Use `->subsumptive'.
(U+66C7): Use `->subsumptive'.
(U-000232A0): Use `->subsumptive'.