Rename Flutter project + binary: cake_wallet -> hash_wallet

The big one. Touches 760+ files. Locks in the user's decision to break
import-line compatibility with upstream cake-tech/cake_wallet in exchange
for a binary named hash_wallet on every platform.

Changes:
- pubspec_description.yaml: project name cake_wallet -> hash_wallet
- 762 Dart files: every 'package:cake_wallet/...' import rewritten to
  'package:hash_wallet/...' (lib/, cw_*/lib/, tool/, test/, integration_test/)
- linux/CMakeLists.txt: BINARY_NAME cake_wallet -> hash_wallet
- windows/CMakeLists.txt: project + BINARY_NAME (CakeWallet -> HashWallet)
- windows/runner/Runner.rc: company / file / product strings to Hash Wallet
  + Such Software LLC copyright
- macos/Runner.xcodeproj/project_base.pbxproj: cake_wallet_new.app refs
  -> hash_wallet.app (macOS output bundle name)
- com.suchsoftware.HashWallet.yml (Flatpak): all binary path refs
  cake_wallet -> hash_wallet (e.g. /app/hash_wallet/hash_wallet)
- linux/com.suchsoftware.HashWallet.desktop: Exec=hash_wallet
- scripts/android/copy_monero_deps.sh: CW_DIR target path
- configure_hash_wallet.sh: error message typo (old filename)

INTENTIONALLY UNCHANGED:
- cw_* subpackage names (cw_core, cw_bitcoin, cw_wownero, etc.) — they
  remain as the historical 'cake wallet' naming; renaming them would
  cascade through every sub-package's internal structure
- Method channel name 'com.cake_wallet/native_utils' in iOS/macOS/Android
  AppDelegates and MainActivity — it's a string identifier that has to
  match the Dart side exactly. Renaming requires both-sides change; it's
  internal-only and not user-visible.
- ghcr.io/cake-tech/cake_wallet:debian13-... docker image references in
  build scripts — that's Cake Labs' published image we use as the build
  environment, not ours.

User data directory now follows the new binary name:
  ~/.local/share/hash_wallet/  (was ~/.local/share/cake_wallet/)
  ~/.config/hash_wallet/       (was ~/.config/cake_wallet/)
Existing users on the old name will need migration if any exist.

linux/CMakeLists.txt

@@ -4,7 +4,7 @@ project(runner LANGUAGES CXX)
 
 # The name of the executable created for the application. Change this to change
 # the on-disk name of your application.
-set(BINARY_NAME "cake_wallet")
+set(BINARY_NAME "hash_wallet")
 # The unique GTK application identifier for this application. See:
 # https://wiki.gnome.org/HowDoI/ChooseApplicationID
 set(APPLICATION_ID "com.suchsoftware.hashwallet")

linux/com.suchsoftware.HashWallet.desktop

@@ -6,4 +6,4 @@ Comment=A noncustodial multi-currency wallet
 Categories=Office;Finance;
 Terminal=false
 Icon=com.suchsoftware.HashWallet
-Exec=cake_wallet
+Exec=hash_wallet