fix: Use cleanSourceWith for better source filtering

Replace sourceFilesBySuffices with cleanSourceWith to ensure
vendor directory and all dependencies are properly included.
This fixes the oban_met compilation error.

nix/build.nix

@@ -11,24 +11,30 @@ beamPackages.mixRelease {
   version = "0.1.0";
 
   # Source files (filtered to exclude build artifacts)
-  src = lib.sourceFilesBySuffices ../. [
-    ".ex"
-    ".exs"
-    ".eex"
-    ".heex"
-    ".leex"
-    ".erl"
-    ".hrl"
-    ".js"
-    ".ts"
-    ".css"
-    ".json"
-    ".proto"
-    ".md"
-    ".txt"
-    ".mib"
-    ".gitignore"
-  ];
+  src = lib.cleanSourceWith {
+    src = ../.;
+    filter =
+      path: type:
+      let
+        baseName = baseNameOf path;
+        parentDir = baseNameOf (dirOf path);
+      in
+      # Exclude build artifacts and temp directories
+      baseName != "_build"
+      && baseName != "deps"
+      && baseName != ".elixir_ls"
+      && baseName != ".elixir-tools"
+      && baseName != "node_modules"
+      && baseName != "cover"
+      && baseName != ".git"
+      && baseName != ".nix-postgres"
+      && baseName != ".nix-redis"
+      && baseName != ".nix-mix"
+      && baseName != ".nix-hex"
+      && baseName != ".worktrees"
+      # Include vendor directory and all its contents
+      && (parentDir == "vendor" || baseName == "vendor" || true);
+  };
 
   # Filter function to include necessary files and directories
   # but exclude build artifacts