Include all available drivers in the default Nix build

Main currently ships a flake with zero DB drivers — SQLite works via
stdlib but nothing else does, and Nix users can't add drivers
post-install. Drop the no-driver default; the out-of-box derivation
now pulls in every extra nixpkgs can satisfy (ssh, postgres,
cockroachdb, mysql, duckdb, bigquery, snowflake, d1). Custom builds
still go through lib.makeSqlit { extras = [ ... ]; }.

Closes the gap reported in #126 and #154.

Author: Maxteabag

README.md

@@ -113,7 +113,7 @@ pip install sqlit-tui
 # Arch Linux (AUR)
 yay -S sqlit
 
-# Nix (flake) — append "#sqlit-full" for common DB drivers
+# Nix (flake)
 nix run github:Maxteabag/sqlit
 ```
 

flake.nix

@@ -98,11 +98,10 @@
             };
           };
 
-        sqlit = makeSqlit { };
-        sqlit-full = makeSqlit { extras = builtins.attrNames nixpkgsExtras; };
+        sqlit = makeSqlit { extras = builtins.attrNames nixpkgsExtras; };
       in {
         packages = {
-          inherit sqlit sqlit-full;
+          inherit sqlit;
           default = sqlit;
         };