feat: new expression language

* add new expression language `{{...}}` with more flexibility
* provide backward-compatibility with old expression syntax `${...}`
* add functions parseDate, formatDate, offsetDate, join
* add date expression examples
* add legacy expression examples
* handle non-published branches in clasp.sh
* add update-parser.sh to generate antlr4-based parser
* improve testing of log actions
* add expectations to e2e tests
* refactor log message cutoff
* improve action execution results
* add log redaction mode
* add MockFactory.newMockFromExample()
* add more babel plugins for GAS compatibility

babel.config.json

@@ -1,3 +1,8 @@
 {
-  "plugins": ["@babel/plugin-transform-class-properties"]
+  "plugins": [
+    "@babel/plugin-transform-class-properties",
+    "@babel/plugin-transform-class-static-block",
+    "@babel/plugin-transform-logical-assignment-operators",
+    "@babel/plugin-transform-private-methods"
+  ]
 }

devbox.json

@@ -7,7 +7,8 @@
     "gomplate@3",
     "google-clasp@2",
     "nodejs@22",
-    "renovate@latest"
+    "renovate@latest",
+    "antlr@4"
   ],
   "shell": {
     "init_hook": ["echo 'Welcome to gmail-processor devbox!' > /dev/null"],