fix: component port labels showing wrong name after editing blueprint

The label lookup in drawComponentGate read from gate.component (potentially
stale copy) while gateOutputCount read from state.customComponents (updated
definition), causing a mismatch — fewer ports but old outputIds, so the
first (deleted) output's label was shown instead of the surviving one.

Three fixes:
- renderer: use customComponents as authoritative source for label lookup
- saveLoad: re-link gate.component refs to customComponents after loading
- components: update existing instances even when a "new" component
  overwrites an existing definition with the same name

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

js/saveLoad.js

@@ -56,6 +56,16 @@ export function loadState(data) {
             state.customComponents = JSON.parse(JSON.stringify(data.components));
         }
 
+        // Re-link gate.component references to customComponents (authoritative source)
+        for (const gate of state.gates) {
+            if (gate.type.startsWith('COMPONENT:')) {
+                const compId = gate.type.substring(10);
+                if (state.customComponents[compId]) {
+                    gate.component = state.customComponents[compId];
+                }
+            }
+        }
+
         // Load progress
         if (data.progress) {
             progress.unlockedLevels = data.progress.unlockedLevels || ['buffer'];