Cost an unknown icon name the icon, not the whole dialog

[wormeyman]

F.CreateIcon ends in a bare throw for a name FD does not have, and those
names come out of the blueprint. UIContainer.createEditor has no try above
it on purpose, so an unguarded call cost the user the whole editor: clicking
the entity did nothing at all.

#286 names one site. Measured, there are six.

The four icon slots

F.SafeIcon at each, which #285 added for exactly this - it warns naming the
icon and returns an empty container.

site	reached by	blueprint field
Recipe.ts:38	MachineEditor, TempEditor	recipe
DisplayPanelIcon.ts:39	DisplayPanelEditor	icon
Modules.ts:40, :68	Editor.addModules	items
Filters.ts:242, :251	ChestEditor, SplitterEditor, InserterEditor	request_filters, filter

The display panel one is the half #285 did not reach. That editor has two
branches: if (connected) draws the read-only conditions list and holds the two
sites #285 guarded, then returns. An unconnected panel - the ordinary one -
falls past it to new DisplayPanelIcon(entity), which was still bare. Both
display panel specs on record set connect_to_logistic_network: true, so both
take the guarded branch and neither could see it.

The two that are not icon slots

These are why guarding Recipe.ts alone does not make the machine editor open,
and neither is findable by grepping CreateIcon.

Preview.generatePreview called the static
OverlayContainer.createEntityInfo with nothing around it, while
OverlayContainer's own instance method wraps the identical call at
OverlayContainer.ts:493. Preview is built by Editor's base constructor, so
this one throw cost every editor its dialog, not one entity type.

EntityInfoPanel.updateVisualization calls getModule, which throws by
design (factorioData.ts:255, added in #55 to tell an absent item from a present
non-module one). It runs from pointerOverEventHandler, so an entity holding an
unknown module threw on hover, before any click, with no dialog involved.

Both warn with console.warn rather than G.logger, which is the toast: they
sit on paths that repeat - every hover, every preview redraw - so a toast each
would be a stream of them. The icon slots raise the toast instead, once, when the
dialog opens.

Coverage

tests/editor-icon-guards.spec.ts, one case per site. Every assertion carries
weight: the dialog count is the bug, the empty page-error list tells a guard from
a throw swallowed higher up, and the toast stops a "fix" that drops the icon
silently.

Mutation checked, each guard reverted in turn against the spec:

reverted	tests failing
Recipe.ts	1 - the recipe test
DisplayPanelIcon.ts	1 - the display panel test
Modules.ts (both)	1 - the module test
Filters.ts (both)	2 - the chest and splitter tests
Preview.ts try/catch	3 - recipe, module and chest
EntityInfoPanel.readModule	1 - the module test

No guard is invisible, and the two Filters arms need both the chest case
(CreateIconWithAmount, amounts on) and the splitter case (CreateIcon, amounts
off) - either alone leaves the other arm unmeasured.

The registry spec's fixture

tests/dialog-registry-leak.spec.ts borrowed the machine editor's throw as the
fixture for its registry half, and its header said so: "that editor is still
broken and this spec does not fix it; it is the fixture precisely because it is
broken."

This removes that fixture. Replacing it with another live bug would only move the
wall one file over - a test that needs a bug to stay unfixed is a test that
argues against fixing it. So the fixture is written down instead:
throwingDialogAttempt() constructs a ThrowingDialog, a Dialog subclass whose
constructor throws after super() and does nothing else, and answers whether it
threw. It is never added to the display tree, which is the point - registration
hangs off the added event.

Re-measured rather than assumed: reverting the registry fix still fails that test
at the keybind assertion, 0 against 1, while the other two pass. The mutation
record's stale entries are corrected in place, including one whose reading no
longer applies at all.

Dialog is now exported from the editor package for that hook, alongside the four
classes already exported only for specs.

Verification

• vp check - 0 warnings, lint errors or type errors across 190 files
• vp test - 221 passed
• npx playwright test - 233 passed, full suite

Closes #286.
Closes #288.

🤖 Generated with Claude Code

https://claude.ai/code/session_016ZkWutgXP9XeVoh2RaAX3S