Add Nix flake development environment with direnv

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -3,3 +3,4 @@
 /tantivy_indexes
 server/tantivy_indexes
 steel_decimal/tests/property_tests.proptest-regressions
+.direnv/

flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "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"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1753549186,
+        "narHash": "sha256-Znl7rzuxKg/Mdm6AhimcKynM7V3YeNDIcLjBuoBcmNs=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "17f6bd177404d6d43017595c5264756764444ab8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "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",
+  "version": 7
+}

flake.nix

@@ -19,16 +19,32 @@
             cargo
             rustfmt
             clippy
+	    cargo-watch
 
             # C build tools (for your linker issue)
             gcc
             binutils
             pkg-config
+            
+            # OpenSSL for crypto dependencies
+            openssl
+            openssl.dev
+            
+            # PostgreSQL for sqlx
+            postgresql
+	    sqlx-cli
+            
+            # Protocol Buffers compiler for gRPC
+            protobuf
           ];
 
           shellHook = ''
+            export PKG_CONFIG_PATH="${pkgs.openssl.dev}/lib/pkgconfig:$PKG_CONFIG_PATH"
+            export OPENSSL_DIR="${pkgs.openssl.dev}"
+            export OPENSSL_LIB_DIR="${pkgs.openssl.out}/lib"
+            export OPENSSL_INCLUDE_DIR="${pkgs.openssl.dev}/include"
             echo "🦀 Rust development environment loaded"
-            echo "Run 'cargo check' to verify everything works"
+            echo "OpenSSL and PostgreSQL available"
           '';
         };
       }