- parse_path_element_with_link splits its fat `if`/or-chain into three
focused helpers: linkable_callsign?/1 (regex + alias check),
path_alias?/1 (four String.starts_with guards), and
classify_path_element/2 (link vs. text dispatched on the boolean).
- display_for_element/2 chooses the callsign form with/without the
asterisk via two function heads instead of an inline `if`.
Adds 7 tests covering the parse_path_with_links/1 public API — plain
callsigns, heard-via asterisk preservation, non-linkable aliases
(WIDE/TRACE/RELAY/TCPIP), q-constructs, whitespace trimming, and mixed
paths.