fix(dropdown): flip-up menu collapses off-screen (follow-up to #59)

[KucharczykL]

Follow-up to #59, which fixed the dropdown clipping but introduced a flip-up regression.

Problem

When a dropdown toggle sits near the viewport bottom, the menu must flip up. In that branch the code cleared inline top with "" — which let the menu's top-[105%] utility class reassert top: 105% on the now-position:fixed element. With bottom also set, the box collapsed to a 2px sliver below the viewport, so toggles near the bottom appeared not to open at all.

The open-down path worked only because it sets inline top explicitly, overriding the class. The original e2e only exercised open-down, so this slipped through.

Measured before (viewport 760, bottom rows): menu top:798 bottom:800 height:2.

Fix

Set the unused anchor to "auto" instead of "" so the inline value wins over the top-[105%] class:

if (openUp) { menu.style.top = "auto";    menu.style.bottom = `${innerHeight - rect.top}px`; }
else        { menu.style.bottom = "auto"; menu.style.top    = `${rect.bottom}px`; }

After fix: flip-up rows open upward, fully on-screen (heights 407–542px).

Tests

Added test_device_dropdown_flips_up_near_viewport_bottom (scrolls so lower rows sit near the viewport bottom, asserts the menu is a real on-screen box, not a sliver). make check green (536 tests).

🤖 Generated with Claude Code

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Staging deployment: https://timetracker-staging-fix-issue-39-dropdown-clipped.fly.dev