fix(companion-win): register watermorph:// protocol + handle open-url

- app.setAsDefaultProtocolClient('watermorph') for runtime registration
- electron-builder protocols config for NSIS installer registry write
- handle watermorph:// deep-link in second-instance + open-url events

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

Author: grauxmusic

CompanionWin/main.js

@@ -17,6 +17,9 @@ const kUA      = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (
 const gotLock = app.requestSingleInstanceLock()
 if (!gotLock) { app.quit(); process.exit(0) }
 
+// Register watermorph:// protocol handler (runtime fallback — installer also handles this)
+app.setAsDefaultProtocolClient('watermorph')
+
 // ── State ────────────────────────────────────────────────────────────────────
 
 let win   = null
@@ -213,10 +216,22 @@ app.whenReady().then(() => {
   registerAutostart()
 })
 
-app.on('second-instance', () => {
+app.on('second-instance', (_event, argv) => {
+  // Handle watermorph:// deep-link from second instance
+  const url = argv.find((a) => a.startsWith('watermorph://'))
+  if (url) handleProtocolUrl(url)
   if (win) { win.show(); win.focus() }
 })
 
+app.on('open-url', (_event, url) => {
+  handleProtocolUrl(url)
+})
+
+function handleProtocolUrl(url) {
+  if (!url.startsWith('watermorph://')) return
+  if (win) { win.show(); win.focus() }
+}
+
 app.on('window-all-closed', (e) => {
   e.preventDefault()  // Keep running in tray
 })

CompanionWin/package.json

@@ -12,6 +12,9 @@
     "appId": "ai.95ent.watermorph.helper",
     "productName": "Water Morph",
     "publish": null,
+    "protocols": [
+      { "name": "Water Morph", "schemes": ["watermorph"] }
+    ],
     "win": {
       "target": [{ "target": "nsis", "arch": ["x64"] }],
       "artifactName": "Water_Morph_1.0.0_Windows.exe"