feat: add Windows update function and switch to upstream paqet repo

Windows client (paqet-client.ps1):
- Added Update-Paqet function with version tracking
- Added Get-InstalledPaqetVersion and Save-PaqetVersion helpers
- Creates backup before updating, restores on failure
- Added menu option 7 for update, moved About to option 8

All platforms:
- Switched paqet binary downloads from SamNet-dev/paqctl to hanselime/paqet
- Updated paqctl.sh PAQET_REPO to hanselime/paqet
- Updated README.md download URLs to hanselime/paqet
- Users now get paqet updates directly from upstream source
- Allows paqctl script releases without affecting paqet binary updates

paqctl.sh

@@ -36,7 +36,7 @@ PAQET_VERSION_PINNED="v1.0.0-alpha.13"
 XRAY_VERSION_PINNED="v26.2.4"
 GFK_VERSION_PINNED="v1.0.0"
 
-PAQET_REPO="SamNet-dev/paqctl"
+PAQET_REPO="hanselime/paqet"
 PAQET_API_URL="https://api.github.com/repos/${PAQET_REPO}/releases/latest"
 INSTALL_DIR="${INSTALL_DIR:-/opt/paqctl}"
 BACKUP_DIR="$INSTALL_DIR/backups"
@@ -1880,7 +1880,7 @@ GFK_VERSION_PINNED="v1.0.0"
 
 INSTALL_DIR="REPLACE_ME_INSTALL_DIR"
 BACKUP_DIR="$INSTALL_DIR/backups"
-PAQET_REPO="SamNet-dev/paqctl"
+PAQET_REPO="hanselime/paqet"
 PAQET_API_URL="https://api.github.com/repos/${PAQET_REPO}/releases/latest"
 GFK_REPO="SamNet-dev/paqctl"
 GFK_BRANCH="main"