[Qt] Make colorimeter correction web-check dialog columns sortable

[eoyilmaz]

Summary

• Closes [Qt] Colorimeter correction web-check dialog columns aren't sortable #958. _WebCheckChooserDialog's QTableWidget now has setSortingEnabled(True), so clicking a column header sorts ascending/descending as usual.
• The ΔE*00 avg/max columns sort numerically instead of lexicographically, via a _NumericTableWidgetItem subclass overriding __lt__() to compare as float (falling back to text comparison for non-numeric placeholders like "Not applicable").
• Fixed a latent bug that sorting would have exposed: accept() picked the selected row's data by indexing the original rows list with the table's visual row number, which is wrong once sorting reorders rows. Each row's source dict is now stashed on its first-column item via Qt.UserRole and read back from the table, independent of sort order.
• Fixed a RecursionError found while testing: the numeric item's non-numeric fallback originally called super().__lt__(other), but PySide's vtable slot for that virtual still resolves back to the Python override regardless of super(), so it recursed infinitely on any pairing involving a non-numeric ΔE*00 value (e.g. CCSS entries showing "Not applicable"). Replaced with a direct text comparison.
• Confirmed against the wx equivalent (colorimeter_correction_web_check_choose in display_cal.py), which uses a plain, unsorted wx.ListCtrl, so this is a net-new Qt enhancement rather than a parity fix.

Test plan

• pytest tests/test_ui_colorimeter_correction_io.py — 19/20 pass (one pre-existing, unrelated ImportController failure present on develop too)
• New tests: sorting is enabled, ΔE*00 columns sort numerically not lexicographically, row selection resolves correctly after sorting, and a regression test for the mixed numeric/non-numeric recursion bug (verified it actually catches the bug by temporarily reintroducing super().__lt__())
• ruff check DisplayCAL/ui/colorimeter_correction_io.py clean