chore: update Nix configurations for Nixcloud and common hosts

- Add Nixcloud host configurations including networking, hardware, and system settings
- Refactor existing configurations for clarity and organization
- Remove unused podman configuration from home-manager
- Update SSH agent settings and session variables in Nixbook host

flake.lock

@@ -183,18 +183,14 @@
     "secrets": {
       "flake": false,
       "locked": {
-        "lastModified": 1760062596,
-        "narHash": "sha256-nFyr+kOCo9PvdHa9JDTWtMRRqgfOqVUvBSfeyQzqDos=",
-        "ref": "refs/heads/main",
-        "rev": "621da7663ad8f975b98b1cdd5756f361e4f4cc05",
-        "revCount": 2,
-        "type": "git",
-        "url": "ssh://git@git.sr.ht/~sposito/secrets"
+        "path": "git@git.sr.ht/~sposito/secrets",
+        "type": "path"
       },
       "original": {
-        "type": "git",
-        "url": "ssh://git@git.sr.ht/~sposito/secrets"
-      }
+        "path": "git@git.sr.ht/~sposito/secrets",
+        "type": "path"
+      },
+      "parent": []
     },
     "sops-nix": {
       "inputs": {