Delete the TelemetryRecorder, CrashReporter, PendingCrashStore and platform
crash hooks along with their models, JSON encoders and the diagnostics opt-in
preference. The DiagnosticsTransport interface is narrowed to sendBugReport, and
DiagnosticsCoordinator now only wires the bug-report service and install id.
Bug reporting, the breadcrumb buffer, log redaction and the diagnostics endpoint
config are kept. Regenerate localization after dropping the diagnostics_* keys.
Ship client-side telemetry, crash capture, and bug-report assembly behind a
user opt-in, with NoOp transport until Cloudflare is wired. Builds can set
vnidrop.diagnostics.included=false to omit the Share-diagnostics UI and
disable the telemetry/crash auto-upload stack while keeping bug reports.