feat(brand): finish desktop chrome rebrand → fee[dB]ack (#23)

main/main split #21 already rebranded splash.html + the splash status
message. This finishes the remaining user-visible chrome:

- Window titles (both BrowserWindows): Slopsmith → fee[dB]ack
- Error dialogs: "failed to start" / "Please restart" (×4) + the
  Velopack updater-error dialog
- macOS mic-permission warning string
- crashReporter productName/companyName label
- package.json: productName → "fee[dB]ack" (+ safe executableName
  "feedback" and artifactName slug so the AppImage/deb filename and
  inner binary avoid the "[dB]" glob metacharacters), description,
  and NSMicrophoneUsageDescription

Deliberately unchanged for continuity:
- package.json "name" (config dir stays ~/.config/slopsmith-desktop —
  testers keep settings/cache) and "appId" (Velopack update identity)
- code comments + the [main] dev console.log

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "slopsmith-desktop",
   "version": "0.2.9",
-  "description": "Slopsmith desktop app with integrated audio engine, VST hosting, and amp modeling",
+  "description": "fee[dB]ack desktop app with integrated audio engine, VST hosting, and amp modeling",
   "author": {
     "name": "Byron",
     "email": "byron@ougsoft.com"
@@ -30,7 +30,9 @@
   },
   "build": {
     "appId": "com.byron.slopsmith-desktop",
-    "productName": "Slopsmith",
+    "productName": "fee[dB]ack",
+    "executableName": "feedback",
+    "artifactName": "feedback-${version}-${arch}.${ext}",
     "directories": {
       "output": "release"
     },
@@ -109,7 +111,7 @@
       "entitlementsInherit": "resources/entitlements.mac.plist",
       "notarize": true,
       "extendInfo": {
-        "NSMicrophoneUsageDescription": "Slopsmith needs microphone access for guitar input and note detection."
+        "NSMicrophoneUsageDescription": "fee[dB]ack needs microphone access for guitar input and note detection."
       },
       "files": [
         "build/Release/slopsmith-vst-scan",