Add Nix flake package outputs for syn-cli, syn-tui, syn-gui

Use crane to build each binary as a separate flake package output.
Track Cargo.lock in git (required for Nix flake source visibility).

.gitignore

@@ -11,7 +11,6 @@ rust/cli-app/tests/stores/
 # Rust
 rust/target/
 rust/**/*.rs.bk
-rust/Cargo.lock
 
 # Android
 *.iml

flake.lock

@@ -1,5 +1,20 @@
 {
   "nodes": {
+    "crane": {
+      "locked": {
+        "lastModified": 1775839657,
+        "narHash": "sha256-SPm9ck7jh3Un9nwPuMGbRU04UroFmOHjLP56T10MOeM=",
+        "owner": "ipetkov",
+        "repo": "crane",
+        "rev": "7cf72d978629469c4bd4206b95c402514c1f6000",
+        "type": "github"
+      },
+      "original": {
+        "owner": "ipetkov",
+        "repo": "crane",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
@@ -36,6 +51,7 @@
     },
     "root": {
       "inputs": {
+        "crane": "crane",
         "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs",
         "rust-overlay": "rust-overlay"

flake.nix

@@ -1,5 +1,5 @@
 {
-  description = "TestAndroid";
+  description = "Synchronicity – personal server runtime";
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
@@ -7,6 +7,7 @@
       url = "github:oxalica/rust-overlay";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    crane.url = "github:ipetkov/crane";
     flake-utils.url = "github:numtide/flake-utils";
   };
 
@@ -14,6 +15,7 @@
     self,
     nixpkgs,
     rust-overlay,
+    crane,
     flake-utils,
   }: let
     rust-version = "1.92.0";
@@ -43,6 +45,74 @@
         rustToolchain = pkgs.rust-bin.stable."${rust-version}".default.override {
           targets = ["aarch64-linux-android"];
         };
+
+        craneLib = (crane.mkLib pkgs).overrideToolchain rustToolchain;
+
+        # Source filtering — include Cargo sources and .slint UI files
+        rustSrc = pkgs.lib.cleanSourceWith {
+          src = ./rust;
+          filter = path: type:
+            (craneLib.filterCargoSources path type)
+            || (builtins.match ".*\\.slint$" path != null);
+        };
+
+        # Common arguments shared across all builds
+        commonArgs = {
+          src = rustSrc;
+          pname = "synchronicity";
+          version = "0.1.0";
+          strictDeps = true;
+
+          nativeBuildInputs = [
+            pkgs.pkg-config
+          ];
+
+          buildInputs = [
+            pkgs.openssl
+          ] ++ pkgs.lib.optionals pkgs.stdenv.isLinux [
+            pkgs.wayland
+            pkgs.libxkbcommon
+            pkgs.fontconfig
+          ];
+        };
+
+        # Build workspace deps once (shared across all binaries)
+        cargoArtifacts = craneLib.buildDepsOnly commonArgs;
+
+        # Helper to build a single binary from the workspace
+        mkBin = name: extraArgs: craneLib.buildPackage (commonArgs // {
+          inherit cargoArtifacts;
+          cargoExtraArgs = "--bin ${name}";
+          # Only install the specific binary
+          doInstallCargoArtifacts = false;
+        } // extraArgs);
+
+        syn-cli = mkBin "syn-cli" {};
+        syn-tui = mkBin "syn-tui" {};
+        syn-gui = mkBin "syn-gui" {
+          buildInputs = commonArgs.buildInputs ++ pkgs.lib.optionals pkgs.stdenv.isLinux [
+            pkgs.libX11
+            pkgs.libxcursor
+            pkgs.libxrandr
+            pkgs.libxi
+            pkgs.libGL
+          ];
+
+          # Slint needs to find wayland/X11 libs at runtime
+          postFixup = pkgs.lib.optionalString pkgs.stdenv.isLinux ''
+            patchelf --add-rpath ${pkgs.lib.makeLibraryPath [
+              pkgs.wayland
+              pkgs.libxkbcommon
+              pkgs.libGL
+              pkgs.libX11
+              pkgs.libxcursor
+              pkgs.libxrandr
+              pkgs.libxi
+              pkgs.fontconfig
+            ]} $out/bin/syn-gui
+          '';
+        };
+
         # CI scripts — source lives in scripts/ for proper shell highlighting
         createReleaseCi = pkgs.writeShellScriptBin "create-release-ci" ''
           export TEA_BIN="${pkgs.tea}/bin/tea"
@@ -57,6 +127,11 @@
           exec bash ${./scripts/build-apk-ci.sh} "$@"
         '';
       in {
+        packages = {
+          inherit syn-cli syn-tui syn-gui;
+          default = syn-cli;
+        };
+
         devShells.default = pkgs.mkShell {
           buildInputs = [
             buildApkCi