fix(minimap, controls): keep a double-click on the canvas chrome off the canvas

[webard]

What

A double-click on the minimap or on the controls panel no longer zooms the canvas underneath.

Why

dblclick zoom is bound to the container — d3's stepped handler in the default mode, AlpineFlow's own in 'toggle' — and both panels are children of that container, so the event bubbled to it.

Two symptoms, one cause:

• Minimap. Two clicks on it are two pans. The canvas jumped to another scale on top of them, so a click meant to move the view moved and rescaled it. Measured in a real app: minimap double-click took the viewport from zoom: 0.31 to zoom: 1 (the toggle level) on top of the pan it had just done.
• Controls. Two quick presses of zoom-in are a double-click as far as the container is concerned. Pressing + twice in a hurry left the canvas at the double-click level instead of one step further in under the cursor — the control and the canvas fighting over the same two clicks.

controls-panel.ts already swallows mousedown, pointerdown and wheel for exactly this reason ("Prevent pan/zoom from triggering when interacting with buttons"); dblclick was the one that got missed. This adds it, and gives the minimap the same treatment for its own panel.

Shape

One stopPropagation per panel, on the panel wrapper. Stopping it there fixes both zoomOnDoubleClick modes at once — neither handler sees an event that never leaves the panel — and it does not touch the buttons: the event is stopped on the way out of the panel, not on the way in.

The minimap's listener is removed in destroy() alongside its siblings, for symmetry with the rest of the file.

Tests

• minimap.test.ts — a double-click on the minimap does not reach the container, and one anywhere else still does.
• controls-panel-fullscreen.test.ts — mousedown / pointerdown / wheel / dblclick all stay inside the panel (the first three pinning the behaviour that was already there), plus a case proving the button's own onZoomIn still fires twice across a double-click, so the fix cannot be "swallow everything".

Both new cases fail against dev without the source change. npm run test — 187 files, 3039 tests, all passing.

Not included

dist/ is not rebuilt — source, tests and docs only. No version bump, no CHANGELOG.md entry, no new dependencies.

One thing I noticed while in minimap.ts and did not change, in case it is deliberate: onWheel calls preventDefault() but not stopPropagation(), so a wheel over the minimap runs the minimap's own zoom and reaches the canvas's wheel zoom. Happy to fix in a follow-up if it is not intended.

Independent of #82 and #83; all three branch off dev and touch different files.