fix(udpscope): make the time-order test actually exercise the swap, guard the font copy

The ramp data in EmitsPointsInTimeOrder never produced a bucket whose maximum
preceded its minimum, so an implementation ordering the emitted pair by value
instead of by time would have passed. Replaced with an explicit two-bucket case
whose second bucket reverses the order.

file(COPY) is a hard configure error on a missing source, so a checkout without
the sibling StreamHub resources failed to configure despite the ASCII-icon
fallback the block above had just selected.

Plan amended to match on both points.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Client/udpscope/CMakeLists.txt

@@ -72,7 +72,11 @@ else()
     message(WARNING "Bundled Font Awesome missing — using ASCII icon fallbacks")
 endif()
 
-file(COPY ${FONT_DIR} DESTINATION ${CMAKE_BINARY_DIR}/resources)
+# Guarded: file(COPY) is a hard configure error on a missing source, which
+# would defeat the fallback the block above just chose.
+if(EXISTS ${FONT_DIR})
+    file(COPY ${FONT_DIR} DESTINATION ${CMAKE_BINARY_DIR}/resources)
+endif()
 
 # ── Core library: everything except main.cpp, so tests can link it ────────────
 set(CORE_SOURCES