Add FunctionalJavascript coverage for the place map and calendar JavaScript

The test suite is 118 classes and just under 500 test methods, split 99 kernel, 14 functional and 5 unit, with zero FunctionalJavascript. The uncovered surface is 2,320 lines of JavaScript: the place map (1,333 lines, covering place selection, panning, the selection panel, pooled-area quantity and price display), the calendar picker (800 lines), and the check-in scanner (187 lines).

That is the headline feature of the 1.0.0-alpha2 cycle going out with no browser coverage, and it has already cost real bugs that no PHP test could catch. #3611882: Graphical seat map: clicking a seat no longer books it (pointer capture swallows the click) was pointer capture swallowing the click, so selecting a place silently booked it. #3611904: Keep the seat map's total and Remove all button visible when the selection list is long was the running total and Remove all button scrolling out of view once the selection list grew. Both were found by hand, after the code shipped.

Proposed resolution. Start with one FunctionalJavascript class over the place map, covering the paths that actually broke: select a place and see it appear in the selection panel with the right tariff, deselect it, remove the whole selection, take a quantity in a pooled area, and confirm the total tracks the selection. A second class over the calendar picker can follow.

This is deliberately not a release blocker for 1.0.0-alpha2, but it is the highest-value test debt in the project, and it will only get more expensive as the map grows features.