nix/hosts/cc-ci: real hardware + networking from the box; document the infect fixes

hardware.nix / networking.nix are now the nixos-infect output of
195.201.88.249 (ESP E079-7D41, eth0 MAC-pinned), with the one edit that
matters: defaultGateway as an attrset with interface = "eth0".

README §2a records what it actually took to get NixOS running on the
Debian 13 image: NO_SWAP=true (tmpfs /tmp), a manual lustration from rescue
mode because 26.05's systemd initrd did not honour NIXOS_LUSTRATE (Debian's
unit files shadowed every NixOS service), and the gateway fix applied via a
chroot rebuild with the nix sandbox off.

flake: cc-ci input back on main (PR #32 merged as f6dbfa3); loops uid pinned
to 1000 so workspace rsyncs by uid line up.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FqkQq3CDmFWcQ7u1LzoyRz

flake.lock

@@ -10,16 +10,15 @@
         ]
       },
       "locked": {
-        "lastModified": 1788811018,
+        "lastModified": 1788812004,
         "narHash": "sha256-Vc7RSeqFHCwlVRhnEEjavuJoyIID+RQdJSygHNA8s8Y=",
-        "ref": "feat/nixos-module-export",
-        "rev": "9b99f81f5f20bde865549912a03ff59ac89b2d7c",
-        "revCount": 1532,
+        "ref": "refs/heads/main",
+        "rev": "f6dbfa368995f4d45de09f4052631fd433c87d5b",
+        "revCount": 1533,
         "type": "git",
         "url": "https://git.autonomic.zone/recipe-maintainers/cc-ci.git"
       },
       "original": {
-        "ref": "feat/nixos-module-export",
         "type": "git",
         "url": "https://git.autonomic.zone/recipe-maintainers/cc-ci.git"
       }