feat: add xontribs, hyprspace, and gcc15-fixes overlay

- packages/xontribs.nix: xontrib-prompt-starship, -broot, -term-integrations
  wheels for use with `programs.xonsh.extraPackages` (or xonsh.override)
- packages/hyprspace.nix + hyprspace flake input (flake=false): rebuild
  plugin against the consumer's hyprland; exposed via overlays.hyprspace
- overlays/gcc15-fixes.nix: hotdoc/kitty/libsecret/xdg-desktop-portal/afdko
  workarounds so fleet nodes on the same pin can opt in with one line
- flake.nix: lift overlays out of eachSystem to the root (overlays.default
  was previously nested per-system, which doesn't match flake schema)

README.md

@@ -4,10 +4,36 @@ Personal Nix flake hub — custom packages and overlays
 
 ## Overview
 
-Personal Nix flake hub for publishing custom packages and overlays. Provides packages for x86_64-linux and aarch64-linux.
+Personal Nix flake hub for publishing custom packages and overlays.
+Provides packages for x86_64-linux and aarch64-linux.
 
 ## Build
 
 ```bash
 nix build .#<package-name>
 ```
+
+## Antigravity
+
+`google-antigravity` (FHS-wrapped) and `google-antigravity-no-fhs` are
+re-exposed from
+[jacopone/antigravity-nix](https://github.com/jacopone/antigravity-nix)
+(MIT). Upstream auto-updates daily via its own GitHub Actions; we just bump
+the flake input and CI caches the build to attic.
+
+When the in-app "new version available" banner appears (or you just want to
+refresh the pin):
+
+```bash
+just antigravity-update    # nix flake update antigravity-nix
+git commit -am "antigravity: bump"
+git push                   # CI rebuilds and pushes to attic
+```
+
+Then, on the consumer:
+
+```bash
+cd ~/projects/servers/emmett
+nix flake update oleks-nixpkgs
+nix run .#deploy
+```

ci/build.py

@@ -39,6 +39,8 @@ run(f"'{attic}' login ci {ATTIC_SERVER} '{ATTIC_TOKEN}'")
 
 # Packages per arch
 packages = ["hello-world", "geesefs", "xonsh"]
+if ARCH == "x86_64-linux":
+    packages += ["google-antigravity", "google-antigravity-no-fhs"]
 if ARCH == "s390x-linux":
     packages += ["attic-client"]
 

flake.lock

@@ -1,5 +1,26 @@
 {
   "nodes": {
+    "antigravity-nix": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1776411505,
+        "narHash": "sha256-7HILfdTOvWzAMmfS3lQV3MDmVrr2Epj8x4c9F3mzOSE=",
+        "owner": "jacopone",
+        "repo": "antigravity-nix",
+        "rev": "9f31d28882185d30c0e3082fbc52dab1cd4e879f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "jacopone",
+        "repo": "antigravity-nix",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
@@ -18,6 +39,24 @@
         "type": "github"
       }
     },
+    "flake-utils_2": {
+      "inputs": {
+        "systems": "systems_2"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "fleet-pins": {
       "inputs": {
         "nixpkgs": "nixpkgs",
@@ -104,7 +143,8 @@
     },
     "root": {
       "inputs": {
-        "flake-utils": "flake-utils",
+        "antigravity-nix": "antigravity-nix",
+        "flake-utils": "flake-utils_2",
         "fleet-pins": "fleet-pins",
         "hyprspace": "hyprspace",
         "nixpkgs": [
@@ -127,6 +167,21 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "systems_2": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
     }
   },
   "root": "root",

flake.nix

@@ -12,6 +12,13 @@
       url = "github:KZDKM/Hyprspace/0467be86b18cfc324fab04afbd40fe9ef80f7fa9";
       flake = false;
     };
+
+    # Google Antigravity packaging. Upstream auto-updates daily; we re-expose
+    # the overlay and build into our attic cache so emmett pulls from there.
+    antigravity-nix = {
+      url = "github:jacopone/antigravity-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs =
@@ -21,6 +28,7 @@
       fleet-pins,
       flake-utils,
       hyprspace,
+      antigravity-nix,
       ...
     }:
     let
@@ -38,6 +46,10 @@
       mkPackages =
         pkgs:
         let
+          sys = pkgs.stdenv.hostPlatform.system;
+          # Antigravity ships a Google-provided x86_64/aarch64 Linux binary.
+          # Skip it for cross targets (e.g. s390x) where it can't run anyway.
+          supportsAntigravity = sys == "x86_64-linux" || sys == "aarch64-linux";
           xontribs = import ./packages/xontribs.nix {
             inherit (pkgs) python3Packages fetchurl;
           };
@@ -53,7 +65,15 @@
         }
         # Xontribs: pass into `programs.xonsh.extraPackages` or
         # `pkgs.xonsh.override { extraPackages = ps: [...]; }`.
-        // xontribs;
+        // xontribs
+        # Antigravity: re-expose jacopone/antigravity-nix's outputs so emmett
+        # consumes a single flake-hub input and our CI builds into attic.
+        // nixpkgs.lib.optionalAttrs supportsAntigravity {
+          inherit (antigravity-nix.packages.${sys})
+            google-antigravity
+            google-antigravity-no-fhs
+            ;
+        };
 
       # Overlay providing Hyprspace. Requires `pkgs.hyprland` to be present
       # (consumer applies the Hyprland flake's overlay first). Kept out of

justfile

@@ -0,0 +1,30 @@
+default:
+    @just --list
+
+# ── Antigravity ────────────────────────────────────────────
+
+# Run antigravity (FHS-wrapped) from the attic cache
+antigravity-run:
+    nix run \
+        --extra-substituters "https://nix-cache-custom.oleks.space/attic-infra-cache-k3s-1" \
+        --extra-trusted-public-keys "attic-infra-cache-k3s-1:qYSNK3DmttQXCFqn1t50qoWGtQNPRFWq9mgQjD05DeU=" \
+        git+https://git.oleks.space/oleks/flake-hub#google-antigravity
+
+# Run antigravity (non-FHS variant) from the attic cache
+antigravity-run-no-fhs:
+    nix run \
+        --extra-substituters "https://nix-cache-custom.oleks.space/attic-infra-cache-k3s-1" \
+        --extra-trusted-public-keys "attic-infra-cache-k3s-1:qYSNK3DmttQXCFqn1t50qoWGtQNPRFWq9mgQjD05DeU=" \
+        git+https://git.oleks.space/oleks/flake-hub#google-antigravity-no-fhs
+
+# Build antigravity (FHS-wrapped)
+antigravity-build:
+    nix build .#google-antigravity --print-build-logs
+
+# Build antigravity (non-FHS variant)
+antigravity-build-no-fhs:
+    nix build .#google-antigravity-no-fhs --print-build-logs
+
+# Pull the latest jacopone/antigravity-nix pin
+antigravity-update:
+    nix flake update antigravity-nix