feat: add missing project files and fix architecture compliance

- Add LICENSE file (MIT)
- Add CONTRIBUTING.md with generator-first workflow guidelines
- Add Makefile with comprehensive development commands
- Add .editorconfig for consistent code formatting
- Add CHANGELOG.md for version tracking
- Remove inconsistent non-variant files that bypassed generator architecture
- Fix installation script to use variant-specific paths (prevent config overwriting)

cli/delta/gitconfig-light-soft.delta

@@ -0,0 +1,22 @@
+# Everforest theme for git-delta
+# Generated from template - do not edit manually
+
+[delta]
+    syntax-theme = none
+    file-style = bold
+    file-decoration-style = none
+    hunk-header-decoration-style = cyan box ul
+    line-numbers = true
+    line-numbers-left-style = cyan
+    line-numbers-right-style = cyan
+    line-numbers-minus-style = red
+    line-numbers-plus-style = green
+    line-numbers-zero-style = "#b3c0b0"
+    minus-style = syntax "#e67e80"
+    minus-emph-style = syntax "#e67e80"
+    plus-style = syntax "#a7c080"
+    plus-emph-style = syntax "#a7c080"
+    zero-style = syntax
+    blame-code-style = syntax
+    blame-format = "{author:<18} ({commit:>8}) {timestamp:^16} "
+    blame-palette = "#a6b0a0" "#b3c0b0" "#c0cdb8"