fix: wownero P0s, fail-closed RNG, iOS scheme, dep pins

- resetToDefault omitted Wownero: the reset button null-crashed and left
  WOW wallets with an empty node list
- accountLabel was missing a return and rendered blank for WOW wallets
- sec_random now throws instead of returning empty bytes when the native
  entropy channel fails or under-delivers
- iOS builds no longer register the leftover cakewallet:// URL scheme
- WOW fee estimate now fetched from the connected daemon's
  get_fee_estimate RPC and cached; the inherited XMR constant table
  remains only as a pre-fetch fallback
- pin cake_backup, flutter_local_authentication, and bech32 git deps to
  their locked SHAs for reproducible builds

pubspec_base.yaml

@@ -38,6 +38,7 @@ dependencies:
   flutter_local_authentication:
     git:
       url: https://github.com/cake-tech/flutter_local_authentication
+      ref: 75c8681ebef62398a87c8ae0cccb7cfddffa9734
   package_info_plus: ^8.0.1
   devicelocale: 0.8.1
   auto_size_text: ^3.0.0
@@ -82,7 +83,7 @@ dependencies:
   cake_backup:
     git:
       url: https://github.com/cake-tech/cake_backup.git
-      ref: main
+      ref: 3aba867dcab6737f6707782f5db15d71f303db38
       version: 1.0.0
   flutter_plugin_android_lifecycle: 2.0.23
   path_provider_android: ^2.2.1
@@ -190,6 +191,7 @@ dependency_overrides:
   bech32:
     git:
       url: https://github.com/cake-tech/bech32.git
+      ref: 05755063b593aa6cca0a4820a318e0ce17de6192
   web3dart:
     git:
       url: https://github.com/cake-tech/web3dart.git