* fix(sub): omit hyphen for empty remark variables
The default INBOUND-EMAIL template left a leading hyphen when an inbound had no remark after display remarks became template-driven in b0c1156dd. Treat a hyphen between adjacent variables as their separator and drop it when it would lead the output or when the value after it is empty, so an empty variable in the middle of a template still leaves a single separator between its neighbours. Literal leading hyphens written into the template are preserved.
* fix(sub): elide the remark separator after leading decoration
The separator between two adjacent tokens was kept as soon as any text had
reached the segment, so a template opening with decoration still rendered
"🌐-john" for an inbound with no remark. Track whether a token has produced
a value rather than testing the accumulated output, so the hyphen is elided
for any prefix that carries no token value of its own, and the builder is no
longer rescanned once per token.
e862d81c60