Read each member's Telegram handle from the new sheet column F (duty
count moves to G) and mention on-duty people as @handle in the weekly
reminder, so they get a real notification. Names without a handle, or
not found in the people list, fall back to plain text.
- sheet.go: add colHandle, Person.Handle; parse handle column
- scheduler.go: resolve names to @mentions via handlesByName/mention
- service.go: widen default SHEET_RANGE to column G
These were never committed (hidden by status.showUntrackedFiles=no): without
go.mod/go.sum a fresh clone would not build, and the source files committed in
abb38e3 were missing their accompanying tests.
Kamil 'Kamaś' Bruchal