feat: centralized error reporting → auto GitHub Issues

PHP (api/index.php):
- reportError() endpoint (POST ?action=report_error): accepts source/type/message/stack/context/ua/version
- _createOrCommentGithubIssue(): creates new issue OR adds comment on existing one (dedup by sha1 fingerprint via GitHub search API)
- _appendErrorLog(): local data/error_reports.log fallback (500 KB rotation)
- _phpErrorReport(): called by set_exception_handler + register_shutdown_function → catches all PHP fatals and uncaught exceptions
- _githubRequest(): minimal curl-based GitHub REST v3 helper
- Rate limit bucket: error_report (20 req/min)
- Labels auto-created: auto-report, php-crash, js-error, kiosk-error, scale-error

JS (assets/js/app.js):
- reportError(payload): single POST to report_error, session-level dedup via _reportedFingerprints Set
- window.onerror: reports uncaught-error with message+stack+location context
- window.unhandledrejection: reports unhandled-promise with reason+stack
- api(): reports api-server-error on HTTP 5xx responses

Android Kiosk:
- ErrorReporter.kt: singleton with init(context, serverUrl), report(Throwable), reportMessage(type, message)
  - Thread.setDefaultUncaughtExceptionHandler → catches ALL unhandled JVM crashes
  - Async executor (single thread), per-session fingerprint dedup, synchronous fallback for crash handler
  - doPost(): HttpURLConnection POST to /api/?action=report_error with device/version info
- KioskActivity: ErrorReporter.init() in onCreate + finishWizard()
  - onReceivedError: reports webview-load-error with URL + error code
  - onConsoleMessage: reports webview-js-error for ERROR level console messages

Config: GITHUB_ISSUE_TOKEN + GITHUB_REPO added to .env.example

.env.example

@@ -20,3 +20,11 @@ TTS_AUTH_TYPE=bearer
 TTS_CONTENT_TYPE=application/json
 TTS_PAYLOAD_KEY=message
 TTS_ENABLED=false
+
+# GitHub Error Reporting (optional but recommended)
+# Creates GitHub Issues automatically on crashes/errors from app, kiosk and server.
+# Create a fine-grained PAT at https://github.com/settings/tokens?type=beta
+#   → Only selected repos: EverShelf
+#   → Permissions: Issues (Read+Write), Metadata (Read-only)
+GITHUB_ISSUE_TOKEN=
+GITHUB_REPO=dadaloop82/EverShelf