Add ESLint and Prettier, and close the node test gaps

Tooling:
- Prettier as the single formatting authority (110 columns, single quotes,
  measured against the existing style); Markdown excluded because table-cell
  padding turns the README glossary into 1000-character lines.
- Type-aware ESLint ending in eslint-config-prettier, so a rule always means
  "this is a bug", never "this looks different".
- .editorconfig and an `npm run check` that runs typecheck, lint, format and
  tests in one go.

Findings fixed on the first run: three more duplicate imports, four
String(unknown) calls (parameter types narrowed instead of casts), two dead
initialisers, two redundant casts, a console.log for a real error. Two
warnings were false here and are disabled with a reason in place.

Tests 132 -> 269:
- node-catalog.test.ts covers every node with a run(), with a guard that fails
  when a new node has no row.
- behavior-events.test.ts covers the ten event nodes through a running World,
  checking timing rather than existence.
- Input's state machine (press/release/releaseAll) is reachable without DOM
  events now; the DOM handlers are thin adapters.

Compare fell back to == without a configured operator although the schema
default is <; aligned.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/core/graph/nodes/action/Move.ts

@@ -10,7 +10,14 @@ export const Move: NodeDef = {
     "Moves an object by (dx, dy) × scale × dt. Connect dt to an event's dt for per-second movement; " +
     'leave it at 1 for per-frame. With "Collide with solids" on, the object\'s solid colliders stop at ' +
     'other solid colliders and slide along them; blocked x/y tell which axes hit.',
-  inputs: [exec(), obj('object'), num('dx'), num('dy'), withDefault(num('scale'), 1), withDefault(num('dt'), 1)],
+  inputs: [
+    exec(),
+    obj('object'),
+    num('dx'),
+    num('dy'),
+    withDefault(num('scale'), 1),
+    withDefault(num('dt'), 1),
+  ],
   outputs: [exec(), bool('blockedX', 'blocked x'), bool('blockedY', 'blocked y')],
   params: [{ key: 'collide', label: 'Collide with solids', kind: 'boolean', default: false }],
   run: (ctx, inputs, params) => {