chore: migrate development environment from Nix flakes to devenv

Replace Nix flake-based development setup with devenv for better
developer experience and more streamlined environment management.

Changes:
  - Remove flake.nix and flake.lock files
  - Add devenv.nix, devenv.yaml, and devenv.lock configuration
  - Update .envrc to use devenv instead of nix develop
  - Remove Docker development setup (compose.dev.yml, docker/mod.just)
  - Expand .gitignore with comprehensive IDE and OS exclusions
  - Remove Docker-related just commands from justfile

Cargo.lock

@@ -415,7 +415,7 @@ dependencies = [
 
 [[package]]
 name = "georm"
-version = "0.1.0"
+version = "0.1.1"
 dependencies = [
  "georm-macros",
  "rand 0.9.0",
@@ -424,7 +424,7 @@ dependencies = [
 
 [[package]]
 name = "georm-macros"
-version = "0.1.0"
+version = "0.1.1"
 dependencies = [
  "deluxe",
  "proc-macro2",