feat: CLK toggles on Step, add pan/zoom (arrows, +/-, wheel, 0=reset)

js/gates.js

@@ -1,7 +1,7 @@
 // Gate evaluation and port geometry
 import { GATE_W, GATE_H, PORT_R, gateInputCount, gateOutputCount } from './constants.js';
 import { state } from './state.js';
-import { recordSample } from './waveform.js';
+import { recordSample, setEvaluateAll } from './waveform.js';
 
 export function getInputPorts(gate) {
     const count = gateInputCount(gate.type);
@@ -61,6 +61,9 @@ export function evaluateAll() {
     if (state.recording && state.waveformVisible) recordSample();
 }
 
+// Register evaluateAll in waveform to break circular dependency
+setEvaluateAll(evaluateAll);
+
 export function findGateAt(x, y) {
     return state.gates.find(g => x >= g.x && x <= g.x + GATE_W && y >= g.y && y <= g.y + GATE_H);
 }