add initial git support

internal/assets/diff/themes/dark.json

@@ -0,0 +1,73 @@
+{
+  "SYNTAX_HIGHLIGHTING_THEME": "dark-plus",
+  "DEFAULT_COLOR": {
+    "color": "#ffffff",
+    "backgroundColor": "#212121"
+  },
+  "COMMIT_HEADER_COLOR": {
+    "color": "#cccccc"
+  },
+  "COMMIT_HEADER_LABEL_COLOR": {
+    "color": "#00000022"
+  },
+  "COMMIT_SHA_COLOR": {
+    "color": "#00eeaa"
+  },
+  "COMMIT_AUTHOR_COLOR": {
+    "color": "#00aaee"
+  },
+  "COMMIT_DATE_COLOR": {
+    "color": "#cccccc"
+  },
+  "COMMIT_MESSAGE_COLOR": {
+    "color": "#cccccc"
+  },
+  "COMMIT_TITLE_COLOR": {
+    "modifiers": [
+      "bold"
+    ]
+  },
+  "FILE_NAME_COLOR": {
+    "color": "#ffdd99"
+  },
+  "BORDER_COLOR": {
+    "color": "#ffdd9966",
+    "modifiers": [
+      "dim"
+    ]
+  },
+  "HUNK_HEADER_COLOR": {
+    "modifiers": [
+      "dim"
+    ]
+  },
+  "DELETED_WORD_COLOR": {
+    "color": "#ffcccc",
+    "backgroundColor": "#ff000033"
+  },
+  "INSERTED_WORD_COLOR": {
+    "color": "#ccffcc",
+    "backgroundColor": "#00ff0033"
+  },
+  "DELETED_LINE_NO_COLOR": {
+    "color": "#00000022",
+    "backgroundColor": "#00000022"
+  },
+  "INSERTED_LINE_NO_COLOR": {
+    "color": "#00000022",
+    "backgroundColor": "#00000022"
+  },
+  "UNMODIFIED_LINE_NO_COLOR": {
+    "color": "#666666"
+  },
+  "DELETED_LINE_COLOR": {
+    "color": "#cc6666",
+    "backgroundColor": "#3a3030"
+  },
+  "INSERTED_LINE_COLOR": {
+    "color": "#66cc66",
+    "backgroundColor": "#303a30"
+  },
+  "UNMODIFIED_LINE_COLOR": {},
+  "MISSING_LINE_COLOR": {}
+}