xlab-gateway: fix IPv6 routing, clean up table names ...

- Remove IPv6 default route from freedom table (1002) — wgnet peer
  doesn't forward IPv6, causing TLS resets on outbound connections
- Remove Tsinghua IPv6 throw route (unnecessary without IPv6 default)
- IPv6 now uses native WAN path instead of WireGuard tunnel
- Rename table 1002 from typo 'wg-to-skywme' to 'freedom-wgnet'

Co-Authored-By: Claude Opus 4.6 <[email protected]>

xlab-gateway: add hardware-configuration.nix, disable wait-online ...

- Import generated hardware-configuration.nix (Intel CPU microcode,
  boot modules for ehci_pci, ahci, nvme, kvm-intel)
- Disable systemd-networkd-wait-online (gateway doesn't need to block
  boot waiting for WireGuard interfaces)

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Add agenix-encrypted secrets and flake.lock ...

- Encrypted WireGuard keys for xlab-gateway (wgnet, skyworks, warp)
- Encrypted WireGuard PSK for wg-to-wgnet
- Placeholder skydick WireGuard secret
- Updated disko.nix with correct NVMe disk ID (MEMPEK1J016GAD)
- Generated flake.lock pinning nixpkgs 24.11, disko, agenix, deploy-rs

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Initial skyworks infrastructure flake ...

Unified NixOS configuration for skydick (storage server) and
xlab-gateway (lab router). Flat module structure with shared
common/users/ssh modules, agenix secrets, disko, and deploy-rs.

Co-Authored-By: Claude Opus 4.6 <[email protected]>